diff --git a/server/src/main/java/server/haengdong/application/EventService.java b/server/src/main/java/server/haengdong/application/EventService.java
index 94c9dbda1..9ad502606 100644
--- a/server/src/main/java/server/haengdong/application/EventService.java
+++ b/server/src/main/java/server/haengdong/application/EventService.java
@@ -5,6 +5,7 @@
 import java.util.List;
 import lombok.RequiredArgsConstructor;
 import org.springframework.stereotype.Service;
+import org.springframework.transaction.annotation.Transactional;
 import server.haengdong.application.request.EventAppRequest;
 import server.haengdong.application.response.ActionAppResponse;
 import server.haengdong.application.response.EventAppResponse;
@@ -20,6 +21,7 @@
 import server.haengdong.exception.HaengdongException;
 
 @RequiredArgsConstructor
+@Transactional(readOnly = true)
 @Service
 public class EventService {
 
@@ -28,6 +30,7 @@ public class EventService {
     private final BillActionRepository billActionRepository;
     private final MemberActionRepository memberActionRepository;
 
+    @Transactional
     public EventAppResponse saveEvent(EventAppRequest request) {
         String token = eventTokenProvider.createToken();
         Event event = request.toEvent(token);
@@ -44,7 +47,8 @@ public EventDetailAppResponse findEvent(String token) {
     }
 
     public List<ActionAppResponse> findActions(String token) {
-        Event event = eventRepository.findByToken(token).orElseThrow(() -> new IllegalArgumentException(""));
+        Event event = eventRepository.findByToken(token)
+                .orElseThrow(() -> new HaengdongException(HaengdongErrorCode.NOT_FOUND_EVENT));
 
         List<BillAction> billActions = billActionRepository.findByAction_Event(event).stream()
                 .sorted(Comparator.comparing(BillAction::getSequence)).toList();
diff --git a/server/src/main/java/server/haengdong/domain/action/MemberActionStatus.java b/server/src/main/java/server/haengdong/domain/action/MemberActionStatus.java
index afcb31337..0a20817fd 100644
--- a/server/src/main/java/server/haengdong/domain/action/MemberActionStatus.java
+++ b/server/src/main/java/server/haengdong/domain/action/MemberActionStatus.java
@@ -1,6 +1,8 @@
 package server.haengdong.domain.action;
 
 import java.util.Arrays;
+import server.haengdong.exception.HaengdongErrorCode;
+import server.haengdong.exception.HaengdongException;
 
 public enum MemberActionStatus {
     IN,
@@ -11,6 +13,7 @@ public static MemberActionStatus of(String status) {
         return Arrays.stream(MemberActionStatus.values())
                 .filter(s -> s.name().equals(status))
                 .findFirst()
-                .orElseThrow(() -> new IllegalArgumentException("Invalid status: " + status));
+                .orElseThrow(() -> new HaengdongException(HaengdongErrorCode.BAD_REQUEST,
+                        "존재하지 않는 인원 변동 액션입니다."));
     }
 }
diff --git a/server/src/main/java/server/haengdong/presentation/response/StepResponse.java b/server/src/main/java/server/haengdong/presentation/response/StepResponse.java
index 354f019df..54b2b06b9 100644
--- a/server/src/main/java/server/haengdong/presentation/response/StepResponse.java
+++ b/server/src/main/java/server/haengdong/presentation/response/StepResponse.java
@@ -37,8 +37,6 @@ public static StepResponse of(List<ActionAppResponse> actions) {
             }
             if (currentActionType.equals("BILL")) {
                 actionsResponse.add(ActionsResponse.of(group, members));
-            } else {
-                actionsResponse.add(ActionsResponse.of(group, Set.of()));
             }
             currentActionType = typeName;
             group.clear();
@@ -53,8 +51,6 @@ public static StepResponse of(List<ActionAppResponse> actions) {
 
         if (currentActionType.equals("BILL")) {
             actionsResponse.add(ActionsResponse.of(group, members));
-        } else {
-            actionsResponse.add(ActionsResponse.of(group, null));
         }
 
         return new StepResponse(actionsResponse);