diff --git a/.github/workflows/build_and_deploy.yml b/.github/workflows/build_and_deploy.yml
index b907a3347..136fe9a8b 100644
--- a/.github/workflows/build_and_deploy.yml
+++ b/.github/workflows/build_and_deploy.yml
@@ -475,16 +475,17 @@ jobs:
             target=$2
             root=$(echo "$1" | grep -q android && echo jniLibs || echo dll)
             dest="lib/src/main/resources/$root/$target"
-            mkdir -p "$dest"
-            cp -v "../../artifacts/voicevox_core_java_api-$artifact_name"/*.{dll,so,dylib} "$dest" || true
-            # こうするしかないはず。echoを使わない書き方があるかもしれないが、シンプルに面倒。
-            # shellcheck disable=SC2086
-            if [ "$(echo $dest/*)" = "$dest/*" ]; then
-              echo "No dll found in $artifact_name"
-              exit 1
-            else
-              echo "$artifact_name => $dest"
-            fi
+            mkdir -p "$artifact_name"
+            case "$target" in
+              windows-*) ext=dll ;;
+              osx-*)     ext=dylib ;;
+              linux-*)   ext=so ;;
+              android-*) ext=so ;;
+              *)         echo "unknown target: $target"; exit 1 ;;
+            esac
+
+            cp -v "../../artifacts/voicevox_core_java_api-$artifact_name"/*."$ext" "$dest"
+            echo "$artifact_name => $dest"
           }
           function clean_dlls() {
             rm -rf lib/src/main/resources/dll