diff --git a/apps/server/src/domains/game/entities/bomb/BombRoomStateStore.ts b/apps/server/src/domains/game/entities/bomb/BombRoomStateStore.ts
index d217a95..b0a7aaf 100644
--- a/apps/server/src/domains/game/entities/bomb/BombRoomStateStore.ts
+++ b/apps/server/src/domains/game/entities/bomb/BombRoomStateStore.ts
@@ -2,7 +2,8 @@
  * BombRoomStateStore
  * ルーム単位の爆弾重複排除状態と採番状態を管理する
  */
-import { config } from "@repo/shared";
+import { issueServerBombId } from "./bombIdentity.js";
+import { shouldBroadcastBombPlaced } from "./bombDedup.js";
 
 /** ルーム単位の爆弾重複排除状態と採番状態を保持するストア */
 export class BombRoomStateStore {
@@ -11,28 +12,20 @@
 
   /** 爆弾設置イベントを配信すべきか判定し，配信時は重複排除状態を更新する */
   public shouldBroadcastBombPlaced(dedupeKey: string, nowMs: number): boolean {
-    this.cleanupExpiredBombDedup(nowMs);
-
-    if (this.bombDedupTable.has(dedupeKey)) {
-      return false;
-    }
-
-    const ttlMs = config.GAME_CONFIG.BOMB_FUSE_MS + config.GAME_CONFIG.BOMB_DEDUP_EXTRA_TTL_MS;
-    this.bombDedupTable.set(dedupeKey, nowMs + ttlMs);
-    return true;
+    return shouldBroadcastBombPlaced({
+      dedupTable: this.bombDedupTable,
+      dedupeKey,
+      nowMs,
+    });
   }
 
   /** セッション単位の連番からサーバー採番の爆弾IDを生成する */
   public issueServerBombId(roomId: string): string {
-    this.bombSerial += 1;
-    return `${roomId}:${this.bombSerial}`;
-  }
-
-  private cleanupExpiredBombDedup(nowMs: number): void {
-    this.bombDedupTable.forEach((expiresAtMs, dedupeKey) => {
-      if (expiresAtMs <= nowMs) {
-        this.bombDedupTable.delete(dedupeKey);
-      }
+    const { bombId, nextSerial } = issueServerBombId({
+      roomId,
+      currentSerial: this.bombSerial,
     });
+    this.bombSerial = nextSerial;
+    return bombId;
   }
 }
diff --git a/apps/server/src/domains/game/entities/bomb/bombDedup.ts b/apps/server/src/domains/game/entities/bomb/bombDedup.ts
new file mode 100644
index 0000000..ff57c39
--- /dev/null
+++ b/apps/server/src/domains/game/entities/bomb/bombDedup.ts
@@ -0,0 +1,40 @@
+/**
+ * bombDedup
+ * 爆弾設置要求の重複排除テーブル操作を提供する
+ */
+import { config } from "@repo/shared";
+
+type ShouldBroadcastBombPlacedParams = {
+  dedupTable: Map<string, number>;
+  dedupeKey: string;
+  nowMs: number;
+};
+
+/** 重複排除テーブルの期限切れエントリを削除する */
+export const cleanupExpiredBombDedup = (
+  dedupTable: Map<string, number>,
+  nowMs: number
+): void => {
+  dedupTable.forEach((expiresAtMs, key) => {
+    if (expiresAtMs <= nowMs) {
+      dedupTable.delete(key);
+    }
+  });
+};
+
+/** 爆弾設置イベントを配信すべきか判定し，配信時は重複排除状態を更新する */
+export const shouldBroadcastBombPlaced = ({
+  dedupTable,
+  dedupeKey,
+  nowMs,
+}: ShouldBroadcastBombPlacedParams): boolean => {
+  cleanupExpiredBombDedup(dedupTable, nowMs);
+
+  if (dedupTable.has(dedupeKey)) {
+    return false;
+  }
+
+  const ttlMs = config.GAME_CONFIG.BOMB_FUSE_MS + config.GAME_CONFIG.BOMB_DEDUP_EXTRA_TTL_MS;
+  dedupTable.set(dedupeKey, nowMs + ttlMs);
+  return true;
+};
diff --git a/apps/server/src/domains/game/entities/bomb/bombIdentity.ts b/apps/server/src/domains/game/entities/bomb/bombIdentity.ts
new file mode 100644
index 0000000..634cf62
--- /dev/null
+++ b/apps/server/src/domains/game/entities/bomb/bombIdentity.ts
@@ -0,0 +1,21 @@
+/**
+ * bombIdentity
+ * 爆弾ID採番ロジックを提供する
+ */
+
+type IssueServerBombIdParams = {
+  roomId: string;
+  currentSerial: number;
+};
+
+/** 次のサーバー採番爆弾IDと更新後シリアルを返す */
+export const issueServerBombId = ({
+  roomId,
+  currentSerial,
+}: IssueServerBombIdParams): { bombId: string; nextSerial: number } => {
+  const nextSerial = currentSerial + 1;
+  return {
+    bombId: `${roomId}:${nextSerial}`,
+    nextSerial,
+  };
+};