diff --git a/src/components/Sing/ScoreSequencer.vue b/src/components/Sing/ScoreSequencer.vue
index 969a2ecc37..3e4728d9c8 100644
--- a/src/components/Sing/ScoreSequencer.vue
+++ b/src/components/Sing/ScoreSequencer.vue
@@ -14,37 +14,36 @@
       <!-- グリッド -->
       <!-- NOTE: 現状小節+オクターブごとの罫線なし -->
       <svg
-        :height="`${sizeY * zoomY * 128}`"
-        :width="`${gridX.length * sizeX * zoomX}`"
+        :width="`${gridWidth * gridNumX}`"
+        :height="`${gridHeight * keyInfos.length}`"
         xmlns="http://www.w3.org/2000/svg"
         class="sequencer-grids"
       >
         <!-- パターングリッド -->
         <defs>
           <pattern
-            id="sequencer-grid-16"
-            :width="`${sizeX * zoomX}px`"
-            :height="`${12 * sizeY * zoomY}px`"
+            id="sequencer-grid-row"
+            :width="`${gridWidth}px`"
+            :height="`${gridHeight * 12}px`"
             patternUnits="userSpaceOnUse"
           >
             <rect
-              v-for="(y, index) in gridY"
+              v-for="(keyInfo, index) in keyInfos"
               :key="index"
               x="0"
-              :y="`${sizeY * zoomY * index}`"
-              :width="`${sizeX * zoomX}`"
-              :height="`${sizeY * zoomY}`"
-              :class="`sequencer-grids-col sequencer-grids-col-${y.color}`"
+              :y="`${gridHeight * index}`"
+              :width="`${gridWidth}`"
+              :height="`${gridHeight}`"
+              :class="`sequencer-grids-col sequencer-grids-col-${keyInfo.color}`"
             />
           </pattern>
-          <!-- NOTE: 4/4 1小節でグリッド見た目確認目的 -->
           <pattern
             id="sequencer-grid-measure"
-            :width="`${sizeX * 16 * zoomX}`"
-            :height="`${12 * sizeY * zoomY}`"
+            :width="`${gridWidth * gridNumXPerMeasure}`"
+            :height="`${gridHeight * 12}`"
             patternUnits="userSpaceOnUse"
           >
-            <rect width="100%" height="100%" fill="url(#sequencer-grid-16)" />
+            <rect width="100%" height="100%" fill="url(#sequencer-grid-row)" />
             <line
               x="100%"
               x2="0"
@@ -117,14 +116,20 @@
 import { defineComponent, computed, ref, onMounted } from "vue";
 import { v4 as uuidv4 } from "uuid";
 import { useStore } from "@/store";
+import { TimeSignature } from "@/store/type";
 import SequencerKeys from "@/components/Sing/SequencerKeys.vue";
 import SequencerNote from "@/components/Sing/SequencerNote.vue";
 import {
-  midiKeys,
-  getPitchFromMidi,
-  getDoremiFromMidi,
-  BASE_GRID_SIZE_X as sizeX,
-  BASE_GRID_SIZE_Y as sizeY,
+  keyInfos,
+  getDoremiFromNoteNumber,
+  getNoteDuration,
+  getKeyBaseHeight,
+  tickToBaseX,
+  baseXToTick,
+  noteNumberToBaseY,
+  baseYToNoteNumber,
+  getTicksPerMeasure,
+  getMeasureNum,
 } from "@/helpers/singHelper";
 
 export default defineComponent({
@@ -152,63 +157,81 @@ export default defineComponent({
     const dragMoveCurrentX = ref();
     const dragMoveCurrentY = ref();
     const dragDurationCurrentX = ref();
-    // シーケンサグリッド
-    const gridY = midiKeys;
-    const gridX = computed(() => {
-      const resolution = state.score?.resolution || 480;
-      // NOTE: 最低長: 仮32小節...MIDI長さ(曲長さ)が決まっていないため、無限スクロール化する or 最後尾に足した場合は伸びるようにするなど？
-      const minDuration = resolution * 4 * 32;
-      const lastNote = state.score?.notes.slice(-1)[0];
-      // Score長さ: スコア長もしくは最低長のうち長い方
-      const totalDuration = lastNote
-        ? Math.max(lastNote.position + lastNote.duration, minDuration)
-        : minDuration;
-      // グリッド幅1/16
-      const gridDuration = resolution / 4;
-      // NOTE: いったん最後尾に足した場合は伸びるようにする
-      const gridsMax = Math.ceil(totalDuration / gridDuration) + 16;
-      return [...Array(gridsMax).keys()].map(
-        (gridNum) => gridNum * gridDuration
-      );
-    });
+    // 分解能（Ticks Per Quarter Note）
+    const tpqn = computed(() => state.score?.resolution ?? 480);
     // ノート
-    const notes = computed(() => state.score?.notes);
-    // 表紙
-    const timeSignatures = computed(() => state.score?.timeSignatures);
+    const notes = computed(() => state.score?.notes ?? []);
+    // 拍子
+    const defaultTimeSignature: TimeSignature = {
+      position: 0,
+      beats: 4,
+      beatType: 4,
+    };
+    const timeSignature = computed(() => {
+      return state.score?.timeSignatures?.[0] ?? defaultTimeSignature;
+    });
     // ズーム状態
     const zoomX = computed(() => state.sequencerZoomX);
     const zoomY = computed(() => state.sequencerZoomY);
     // スナップサイズ
-    const snapSize = computed(() => state.sequencerSnapSize);
-    const snapWidth = computed(() => (snapSize.value / 4) * zoomX.value);
+    const snapSizeTicks = computed(() => {
+      return getNoteDuration(state.sequencerSnapType, tpqn.value);
+    });
+    const snapSizeBaseX = computed(() => {
+      return tickToBaseX(snapSizeTicks.value, tpqn.value);
+    });
+    const snapWidth = computed(() => snapSizeBaseX.value * zoomX.value);
     // グリッドサイズ
-    const gridWidth = computed(() => sizeX * zoomX.value);
-    const gridHeight = computed(() => sizeY * zoomY.value);
+    const gridSizeTicks = snapSizeTicks;
+    const gridSizeBaseX = snapSizeBaseX;
+    const gridSizeBaseY = getKeyBaseHeight();
+    const gridWidth = computed(() => gridSizeBaseX.value * zoomX.value);
+    const gridHeight = computed(() => gridSizeBaseY * zoomY.value);
+    // シーケンサグリッド
+    const ticksPerMeasure = computed(() => {
+      return getTicksPerMeasure(timeSignature.value, tpqn.value);
+    });
+    const gridNumXPerMeasure = computed(() => {
+      // TODO: スナップが3連符のときにおかしくなるので修正する
+      return Math.round(ticksPerMeasure.value / gridSizeTicks.value);
+    });
+    const gridNumX = computed(() => {
+      // NOTE: 最低長: 仮32小節...スコア長(曲長さ)が決まっていないため、無限スクロール化する or 最後尾に足した場合は伸びるようにするなど？
+      const minMeasureNum = 32;
+      const measureNum = Math.max(
+        minMeasureNum,
+        getMeasureNum(notes.value, ticksPerMeasure.value)
+      );
+      // NOTE: いったん最後尾に足した場合は伸びるようにする
+      return gridNumXPerMeasure.value * (measureNum + 1);
+    });
     // スクロール位置
     // const scrollX = computed(() => state.sequencerScrollX);
-    const scrollY = computed(() => state.sequencerScrollY);
+    // const scrollY = computed(() => state.sequencerScrollY);
     const selectedNoteIds = computed(() => state.selectedNoteIds);
 
     // ノートの追加
     const addNote = (event: MouseEvent) => {
-      const resolution = state.score?.resolution;
-      const gridXSize = resolution ? resolution / 4 : snapSize.value;
-      const position =
-        gridXSize * Math.floor(event.offsetX / (sizeX * zoomX.value));
-      const midi = 127 - Math.floor(event.offsetY / (sizeY * zoomY.value));
-      if (0 > midi) {
+      const eventOffsetBaseX = event.offsetX / zoomX.value;
+      const eventOffsetBaseY = event.offsetY / zoomY.value;
+      const positionBaseX =
+        gridSizeBaseX.value *
+        Math.floor(eventOffsetBaseX / gridSizeBaseX.value);
+      const position = baseXToTick(positionBaseX, tpqn.value);
+      const noteNumber = baseYToNoteNumber(eventOffsetBaseY);
+      if (noteNumber < 0) {
         return;
       }
       // NOTE: ノートの追加は1/8をベース
-      const duration = gridXSize * 2;
-      const lyric = getDoremiFromMidi(midi);
+      const duration = getNoteDuration(8, tpqn.value);
+      const lyric = getDoremiFromNoteNumber(noteNumber);
       // NOTE: 仮ID
       const id = uuidv4();
       store.dispatch("ADD_NOTE", {
         note: {
           id,
           position,
-          midi,
+          midi: noteNumber,
           duration,
           lyric,
         },
@@ -258,7 +281,8 @@ export default defineComponent({
       // カーソル位置に応じてノート移動量を計算
       let amountPositionX = 0;
       if (gridWidth.value <= Math.abs(distanceX)) {
-        amountPositionX = 0 < distanceX ? snapSize.value : -snapSize.value;
+        amountPositionX =
+          0 < distanceX ? snapSizeTicks.value : -snapSizeTicks.value;
         const dragMoveCurrentXNext =
           dragMoveCurrentX.value +
           (0 < amountPositionX ? gridWidth.value : -gridWidth.value);
@@ -273,7 +297,7 @@ export default defineComponent({
         dragMoveCurrentY.value = dragMoveCurrentYNext;
       }
 
-      // 選択中のノートのpositionとmidiを変更
+      // 選択中のノートのpositionとnoteNumberを変更
       let isNotesChanged = false;
       const newNotes = [...state.score.notes].map((note) => {
         if (selectedNoteIds.value.includes(note.id)) {
@@ -282,10 +306,10 @@ export default defineComponent({
           }
           isNotesChanged = true;
           const position = note.position + amountPositionX;
-          const midi = note.midi + amountPositionY;
+          const noteNumber = note.midi + amountPositionY;
           return {
             ...note,
-            midi,
+            midi: noteNumber,
             position,
           };
         } else {
@@ -333,8 +357,11 @@ export default defineComponent({
           if (selectedNoteIds.value.includes(note.id)) {
             const duration =
               note.duration +
-              (0 < distanceX ? snapSize.value : -snapSize.value);
-            if (duration < Math.max(snapSize.value, 0) || note.position < 0) {
+              (0 < distanceX ? snapSizeTicks.value : -snapSizeTicks.value);
+            if (
+              duration < Math.max(snapSizeTicks.value, 0) ||
+              note.position < 0
+            ) {
               return note;
             } else {
               isNotesChanged = true;
@@ -385,11 +412,14 @@ export default defineComponent({
           if (selectedNoteIds.value.includes(note.id)) {
             const position =
               note.position +
-              (0 < distanceX ? snapSize.value : -snapSize.value);
+              (0 < distanceX ? snapSizeTicks.value : -snapSizeTicks.value);
             const duration =
               note.duration +
-              (0 > distanceX ? snapSize.value : -snapSize.value);
-            if (duration < Math.max(snapSize.value, 0) || note.position < 0) {
+              (0 > distanceX ? snapSizeTicks.value : -snapSizeTicks.value);
+            if (
+              duration < Math.max(snapSizeTicks.value, 0) ||
+              note.position < 0
+            ) {
               return note;
             } else {
               isNotesChanged = true;
@@ -451,10 +481,10 @@ export default defineComponent({
       }
       const newNotes = state.score.notes.map((note) => {
         if (selectedNoteIds.value.includes(note.id)) {
-          const midi = Math.min(note.midi + 1, 127);
+          const noteNumber = Math.min(note.midi + 1, 127);
           return {
             ...note,
-            midi,
+            midi: noteNumber,
           };
         } else {
           return note;
@@ -472,10 +502,10 @@ export default defineComponent({
       }
       const newNotes = state.score.notes.map((note) => {
         if (selectedNoteIds.value.includes(note.id)) {
-          const midi = Math.max(note.midi - 1, 0);
+          const noteNumber = Math.max(note.midi - 1, 0);
           return {
             ...note,
-            midi,
+            midi: noteNumber,
           };
         } else {
           return note;
@@ -493,7 +523,7 @@ export default defineComponent({
       }
       const newNotes = state.score.notes.map((note) => {
         if (selectedNoteIds.value.includes(note.id)) {
-          const position = note.position + snapSize.value;
+          const position = note.position + snapSizeTicks.value;
           return {
             ...note,
             position,
@@ -511,7 +541,7 @@ export default defineComponent({
       }
       const newNotes = state.score.notes.map((note) => {
         if (selectedNoteIds.value.includes(note.id)) {
-          const position = note.position - snapSize.value;
+          const position = note.position - snapSizeTicks.value;
           return {
             ...note,
             position,
@@ -557,24 +587,26 @@ export default defineComponent({
 
     onMounted(() => {
       const el = document.querySelector("#score-sequencer");
-      // C4あたりにスクロールする
+      // 上から2/3の位置がC4になるようにスクロールする
       if (el) {
-        el.scrollTop = scrollY.value * (sizeY * zoomY.value);
+        const c4BaseY = noteNumberToBaseY(60);
+        const clientBaseHeight = el.clientHeight / zoomY.value;
+        const scrollBaseY = c4BaseY - clientBaseHeight * (2 / 3);
+        el.scrollTop = scrollBaseY * zoomY.value;
       }
     });
 
     return {
-      timeSignatures,
-      gridY,
-      gridX,
+      gridWidth,
+      gridHeight,
+      gridNumXPerMeasure,
+      gridNumX,
+      keyInfos,
       notes,
       zoomX,
       zoomY,
-      sizeX,
-      sizeY,
       cursorX,
       cursorY,
-      getPitchFromMidi,
       setZoomX,
       setZoomY,
       addNote,
diff --git a/src/components/Sing/SequencerKeys.vue b/src/components/Sing/SequencerKeys.vue
index cdac074d39..7cc6bb60f2 100644
--- a/src/components/Sing/SequencerKeys.vue
+++ b/src/components/Sing/SequencerKeys.vue
@@ -1,37 +1,37 @@
 <template>
   <svg
     width="48"
-    :height="`${sizeY * zoomY * 128}`"
+    :height="`${keyHeight * keyInfos.length}`"
     xmlns="http://www.w3.org/2000/svg"
     class="sequencer-keys"
   >
-    <g v-for="(y, index) in gridY" :key="index">
+    <g v-for="(keyInfo, index) in keyInfos" :key="index">
       <rect
         x="0"
-        :y="`${sizeY * zoomY * index}`"
-        :width="`${y.color === 'black' ? 30 : 48}`"
-        :height="`${sizeY * zoomY}`"
-        :class="`sequencer-keys-item-${y.color}`"
-        :title="y.name"
+        :y="`${keyHeight * index}`"
+        :width="`${keyInfo.color === 'black' ? 30 : 48}`"
+        :height="`${keyHeight}`"
+        :class="`sequencer-keys-item-${keyInfo.color}`"
+        :title="keyInfo.name"
       />
       <line
-        v-if="y.pitch === 'C' || y.pitch === 'F'"
+        v-if="keyInfo.pitch === 'C' || keyInfo.pitch === 'F'"
         x1="0"
         x2="48"
-        :y1="`${(index + 1) * sizeY * zoomY}`"
-        :y2="`${(index + 1) * sizeY * zoomY}`"
+        :y1="`${(index + 1) * keyHeight}`"
+        :y2="`${(index + 1) * keyHeight}`"
         :class="`sequencer-keys-item-separator ${
-          y.pitch === 'C' && 'sequencer-keys-item-separator-octave'
-        } ${y.pitch === 'F' && 'sequencer-keys-item-separator-f'}`"
+          keyInfo.pitch === 'C' && 'sequencer-keys-item-separator-octave'
+        } ${keyInfo.pitch === 'F' && 'sequencer-keys-item-separator-f'}`"
       />
       <text
-        v-if="y.pitch === 'C'"
+        v-if="keyInfo.pitch === 'C'"
         font-size="10"
         x="32"
-        :y="`${sizeY * zoomY * (index + 1) - 4}`"
+        :y="`${keyHeight * (index + 1) - 4}`"
         class="sequencer-keys-item-pitchname"
       >
-        {{ y.name }}
+        {{ keyInfo.name }}
       </text>
     </g>
   </svg>
@@ -40,25 +40,21 @@
 <script lang="ts">
 import { defineComponent, computed } from "vue";
 import { useStore } from "@/store";
-import {
-  midiKeys,
-  BASE_GRID_SIZE_X as sizeX,
-  BASE_GRID_SIZE_Y as sizeY,
-} from "@/helpers/singHelper";
+import { keyInfos, getKeyBaseHeight } from "@/helpers/singHelper";
 
 export default defineComponent({
   name: "SingSequencerKeys",
   setup() {
     const store = useStore();
-    const gridY = midiKeys;
     const zoomX = computed(() => store.state.sequencerZoomX);
     const zoomY = computed(() => store.state.sequencerZoomY);
+    const keyBaseHeight = getKeyBaseHeight();
+    const keyHeight = computed(() => keyBaseHeight * zoomY.value);
     return {
-      gridY,
-      sizeX,
-      sizeY,
+      keyInfos,
       zoomX,
       zoomY,
+      keyHeight,
     };
   },
 });
diff --git a/src/components/Sing/SequencerNote.vue b/src/components/Sing/SequencerNote.vue
index a260c04eb6..b0c9246849 100644
--- a/src/components/Sing/SequencerNote.vue
+++ b/src/components/Sing/SequencerNote.vue
@@ -19,7 +19,7 @@
       class="sequencer-note-bar"
       focusable="true"
       tabindex="0"
-      @dblclick.prevent="removeNote"
+      @dblclick.prevent.stop="removeNote"
       @keydown.prevent="handleKeydown"
     >
       <g>
@@ -43,8 +43,8 @@
         />
         <rect
           y="-25%"
-          :x="`${(note.duration / 4) * zoomX - 4}`"
-          width="16"
+          :x="`${barWidth - 4}`"
+          width="12"
           height="150%"
           fill-opacity="0"
           class="sequencer-note-bar-draghandle"
@@ -60,8 +60,9 @@ import { defineComponent, computed, PropType } from "vue";
 import { useStore } from "@/store";
 import { Note } from "@/store/type";
 import {
-  BASE_GRID_SIZE_X as sizeX,
-  BASE_GRID_SIZE_Y as sizeY,
+  getKeyBaseHeight,
+  tickToBaseX,
+  noteNumberToBaseY,
 } from "@/helpers/singHelper";
 
 export default defineComponent({
@@ -82,16 +83,28 @@ export default defineComponent({
 
   setup(props, { emit }) {
     const store = useStore();
-    const zoomX = computed(() => store.state.sequencerZoomX);
-    const zoomY = computed(() => store.state.sequencerZoomY);
-    const positionX = computed(() => (props.note.position / 4) * zoomX.value);
-    const positionY = computed(
-      () => (127 - props.note.midi) * sizeY * zoomY.value
-    );
-    const barHeight = computed(() => sizeY * zoomY.value);
-    const barWidth = computed(() => (props.note.duration / 4) * zoomX.value);
+    const state = store.state;
+    const tpqn = computed(() => state.score?.resolution ?? 480);
+    const zoomX = computed(() => state.sequencerZoomX);
+    const zoomY = computed(() => state.sequencerZoomY);
+    const positionX = computed(() => {
+      const noteStartTicks = props.note.position;
+      return tickToBaseX(noteStartTicks, tpqn.value) * zoomX.value;
+    });
+    const positionY = computed(() => {
+      const noteNumber = props.note.midi;
+      return noteNumberToBaseY(noteNumber + 0.5) * zoomY.value;
+    });
+    const barHeight = computed(() => getKeyBaseHeight() * zoomY.value);
+    const barWidth = computed(() => {
+      const noteStartTicks = props.note.position;
+      const noteEndTicks = props.note.position + props.note.duration;
+      const noteStartBaseX = tickToBaseX(noteStartTicks, tpqn.value);
+      const noteEndBaseX = tickToBaseX(noteEndTicks, tpqn.value);
+      return (noteEndBaseX - noteStartBaseX) * zoomX.value;
+    });
     const isSelected = computed(() => {
-      return store.state.selectedNoteIds.includes(props.note.id);
+      return state.selectedNoteIds.includes(props.note.id);
     });
 
     const removeNote = () => {
@@ -118,8 +131,8 @@ export default defineComponent({
     };
 
     const handleMouseDown = (event: MouseEvent) => {
-      if (!store.state.selectedNoteIds.includes(props.note.id)) {
-        const noteIds = [...store.state.selectedNoteIds, props.note.id];
+      if (!state.selectedNoteIds.includes(props.note.id)) {
+        const noteIds = [...state.selectedNoteIds, props.note.id];
         store.dispatch("SET_SELECTED_NOTE_IDS", {
           noteIds,
         });
@@ -129,7 +142,7 @@ export default defineComponent({
     };
 
     const handleDragRightStart = (event: MouseEvent) => {
-      const noteIds = [...store.state.selectedNoteIds, props.note.id];
+      const noteIds = [...state.selectedNoteIds, props.note.id];
       store.dispatch("SET_SELECTED_NOTE_IDS", {
         noteIds,
       });
@@ -137,7 +150,7 @@ export default defineComponent({
     };
 
     const handleDragLeftStart = (event: MouseEvent) => {
-      const noteIds = [...store.state.selectedNoteIds, props.note.id];
+      const noteIds = [...state.selectedNoteIds, props.note.id];
       store.dispatch("SET_SELECTED_NOTE_IDS", {
         noteIds,
       });
@@ -145,8 +158,6 @@ export default defineComponent({
     };
 
     return {
-      sizeX,
-      sizeY,
       zoomX,
       zoomY,
       positionX,
diff --git a/src/helpers/singHelper.ts b/src/helpers/singHelper.ts
index c0855b302e..81ee302cc9 100644
--- a/src/helpers/singHelper.ts
+++ b/src/helpers/singHelper.ts
@@ -1,5 +1,59 @@
-export function getPitchFromMidi(midi: number): string {
-  const mapPitches: Array<string> = [
+import { Note, TimeSignature } from "@/store/type";
+
+const BASE_X_PER_QUARTER_NOTE = 120;
+const BASE_Y_PER_NOTE_NUMBER = 30;
+
+export function noteNumberToFrequency(noteNumber: number) {
+  return 440 * 2 ** ((noteNumber - 69) / 12);
+}
+
+export function getTicksPerMeasure(timeSignature: TimeSignature, tpqn: number) {
+  const beats = timeSignature.beats;
+  const beatType = timeSignature.beatType;
+  const quarterNotesPerMeasure = (4 / beatType) * beats;
+  return tpqn * quarterNotesPerMeasure;
+}
+
+export function getMeasureNum(notes: Note[], ticksPerMeasure: number) {
+  if (notes.length === 0) {
+    return 0;
+  }
+  const lastNote = notes[notes.length - 1];
+  const maxTicks = lastNote.position + lastNote.duration;
+  return Math.ceil(maxTicks / ticksPerMeasure);
+}
+
+export function getNoteDuration(noteType: number, tpqn: number) {
+  return (tpqn * 4) / noteType;
+}
+
+export function getKeyBaseHeight() {
+  return BASE_Y_PER_NOTE_NUMBER;
+}
+
+export function tickToBaseX(ticks: number, tpqn: number) {
+  return (ticks / tpqn) * BASE_X_PER_QUARTER_NOTE;
+}
+
+export function baseXToTick(baseX: number, tpqn: number) {
+  return (baseX / BASE_X_PER_QUARTER_NOTE) * tpqn;
+}
+
+// NOTE: ノート番号が整数のときに、そのノート番号のキーの中央の位置を返します
+export function noteNumberToBaseY(noteNumber: number) {
+  return (127.5 - noteNumber) * BASE_Y_PER_NOTE_NUMBER;
+}
+
+// NOTE: integerがfalseの場合は、ノート番号のキーの中央の位置が
+//       ちょうどそのノート番号となるように計算します
+export function baseYToNoteNumber(baseY: number, integer = true) {
+  return integer
+    ? 127 - Math.floor(baseY / BASE_Y_PER_NOTE_NUMBER)
+    : 127.5 - baseY / BASE_Y_PER_NOTE_NUMBER;
+}
+
+export function getPitchFromNoteNumber(noteNumber: number) {
+  const mapPitches = [
     "C",
     "C#",
     "D",
@@ -13,12 +67,12 @@ export function getPitchFromMidi(midi: number): string {
     "A#",
     "B",
   ];
-  const pitchPos = midi % 12;
+  const pitchPos = noteNumber % 12;
   return mapPitches[pitchPos];
 }
 
-export function getDoremiFromMidi(midi: number): string {
-  const mapPitches: Array<string> = [
+export function getDoremiFromNoteNumber(noteNumber: number) {
+  const mapPitches = [
     "ド",
     "ド",
     "レ",
@@ -32,28 +86,28 @@ export function getDoremiFromMidi(midi: number): string {
     "ラ",
     "シ",
   ];
-  const pitchPos = midi % 12;
+  const pitchPos = noteNumber % 12;
   return mapPitches[pitchPos];
 }
 
-export function getOctaveFromMidi(midi: number): number {
-  return Math.floor(midi / 12) - 1;
+export function getOctaveFromNoteNumber(noteNumber: number) {
+  return Math.floor(noteNumber / 12) - 1;
 }
 
-export function getKeyColorFromMidi(midi: number): string {
-  const mapWhiteKeys: Array<string> = ["C", "D", "E", "F", "G", "A", "B"];
-  const pitch = getPitchFromMidi(midi);
+export function getKeyColorFromNoteNumber(noteNumber: number) {
+  const mapWhiteKeys = ["C", "D", "E", "F", "G", "A", "B"];
+  const pitch = getPitchFromNoteNumber(noteNumber);
   return mapWhiteKeys.includes(pitch) ? "white" : "black";
 }
 
-export const midiKeys = [...Array(128)]
-  .map((_, midi) => {
-    const pitch = getPitchFromMidi(midi);
-    const octave = getOctaveFromMidi(midi);
+export const keyInfos = [...Array(128)]
+  .map((_, noteNumber) => {
+    const pitch = getPitchFromNoteNumber(noteNumber);
+    const octave = getOctaveFromNoteNumber(noteNumber);
     const name = `${pitch}${octave}`;
-    const color = getKeyColorFromMidi(midi);
+    const color = getKeyColorFromNoteNumber(noteNumber);
     return {
-      midi,
+      noteNumber,
       pitch,
       octave,
       name,
@@ -62,14 +116,7 @@ export const midiKeys = [...Array(128)]
   })
   .reverse();
 
-export const BASE_GRID_SIZE_X = 30;
-export const BASE_GRID_SIZE_Y = 30;
-
 export function round(value: number, digits: number) {
   const powerOf10 = 10 ** digits;
   return Math.round(value * powerOf10) / powerOf10;
 }
-
-export function midiToFrequency(midi: number) {
-  return 440 * 2 ** ((midi - 69) / 12);
-}
diff --git a/src/store/singing.ts b/src/store/singing.ts
index 3798097cc5..4976087ccd 100644
--- a/src/store/singing.ts
+++ b/src/store/singing.ts
@@ -29,8 +29,8 @@ import {
 } from "@/infrastructures/AudioRenderer";
 import { EngineId, StyleId } from "@/type/preload";
 import {
-  getDoremiFromMidi,
-  midiToFrequency,
+  getDoremiFromNoteNumber,
+  noteNumberToFrequency,
   round,
 } from "@/helpers/singHelper";
 import { AudioQuery } from "@/openapi";
@@ -275,9 +275,9 @@ export const singingStoreState: SingingStoreState = {
   isShowSinger: true,
   sequencerZoomX: 0.5,
   sequencerZoomY: 0.75,
-  sequencerScrollY: 60, // Y軸 midi number
-  sequencerScrollX: 0, // X軸 midi duration(仮)
-  sequencerSnapSize: 120, // スナップサイズ 試行用で1/18(ppq=480)のmidi durationで固定
+  sequencerScrollY: 60, // Y軸 note number
+  sequencerScrollX: 0, // X軸 tick(仮)
+  sequencerSnapType: 16, // スナップタイプ 試行用で1/16で固定
   selectedNoteIds: [], // 選択中のノート
   nowPlaying: false,
   volume: 0,
@@ -992,7 +992,7 @@ export const singingStore = createPartialStore<SingingStoreTypes>({
             mora.vowelLength = Math.max(0.001, vowelLength);
 
             // 音高を編集
-            const freq = midiToFrequency(note.midi);
+            const freq = noteNumberToFrequency(note.midi);
             mora.pitch = Math.log(freq);
 
             noteIndex++;
@@ -1283,7 +1283,7 @@ export const singingStore = createPartialStore<SingingStoreTypes>({
               note.durationTicks
             ),
             midi: note.midi,
-            lyric: getDoremiFromMidi(note.midi),
+            lyric: getDoremiFromNoteNumber(note.midi),
           }))
           .sort((a, b) => a.position - b.position)
           .forEach((note) => {
diff --git a/src/store/type.ts b/src/store/type.ts
index d6c0a32049..d998b089e4 100644
--- a/src/store/type.ts
+++ b/src/store/type.ts
@@ -751,7 +751,7 @@ export type SingingStoreState = {
   sequencerZoomY: number;
   sequencerScrollX: number;
   sequencerScrollY: number;
-  sequencerSnapSize: number;
+  sequencerSnapType: number;
   selectedNoteIds: string[];
   nowPlaying: boolean;
   volume: number;
diff --git a/tests/unit/store/Vuex.spec.ts b/tests/unit/store/Vuex.spec.ts
index b0f7d8fd87..22c2a9afad 100644
--- a/tests/unit/store/Vuex.spec.ts
+++ b/tests/unit/store/Vuex.spec.ts
@@ -153,7 +153,7 @@ describe("store/vuex.js test", () => {
         sequencerZoomY: 1,
         sequencerScrollX: 0,
         sequencerScrollY: 60,
-        sequencerSnapSize: 120,
+        sequencerSnapType: 16,
         selectedNoteIds: [],
         nowPlaying: false,
         volume: 0,