diff --git a/packages/shared/src/protocol/eventPayloadMaps.ts b/packages/shared/src/protocol/eventPayloadMaps.ts
index 406c312..eabb623 100644
--- a/packages/shared/src/protocol/eventPayloadMaps.ts
+++ b/packages/shared/src/protocol/eventPayloadMaps.ts
@@ -1,57 +1,35 @@
 /**
  * eventPayloadMaps
- * イベント方向ごとのペイロード対応表を定義する
- * イベント名定数とペイロード型の対応契約を集約する
+ * イベント方向ごとのペイロード対応表を再公開するエントリ
+ * 機能別に分割した対応表を合成して公開契約を維持する
  */
-import { SocketEvents } from "./socketEvents";
 import type {
-  BombPlacedPayload,
-  CurrentPlayersPayload,
-  GameResultPayload,
-  GameStartPayload,
-  JoinRoomPayload,
-  MovePayload,
-  NewPlayerPayload,
-  PingPayload,
-  PongPayload,
-  RemovePlayerPayload,
-  RoomJoinRejectedPayload,
-  RoomUpdatePayload,
-  UpdateMapCellsPayload,
-  UpdatePlayersPayload,
-} from "./eventPayloads";
+  ConnectionLifecycleEventPayloadMap as CommonConnectionLifecycleEventPayloadMap,
+} from "./maps/commonEventPayloadMap";
+import type {
+  LobbyClientToServerEventPayloadMap,
+  LobbyServerToClientEventPayloadMap,
+} from "./maps/lobbyEventPayloadMap";
+import type {
+  GameClientToServerEventPayloadMap,
+  GameServerToClientEventPayloadMap,
+} from "./maps/gameEventPayloadMap";
+
+/** 接続ライフサイクルイベントのペイロード対応表を再公開する */
+export type { ConnectionLifecycleEventPayloadMap } from "./maps/commonEventPayloadMap";
 
 /** 接続ライフサイクルイベントのペイロード対応表 */
-export type ConnectionLifecycleEventPayloadMap = {
-  [SocketEvents.CONNECT]: undefined;
-  [SocketEvents.DISCONNECT]: undefined;
-};
+type ConnectionLifecycleEventPayloadMap = CommonConnectionLifecycleEventPayloadMap;
 
 /** クライアントからサーバーへ送信するイベントごとのペイロード対応表 */
-export type ClientToServerEventPayloadMap = {
-  [SocketEvents.JOIN_ROOM]: JoinRoomPayload;
-  [SocketEvents.START_GAME]: undefined;
-  [SocketEvents.READY_FOR_GAME]: undefined;
-  [SocketEvents.MOVE]: MovePayload;
-  [SocketEvents.PLACE_BOMB]: BombPlacedPayload;
-  [SocketEvents.PING]: PingPayload;
-};
+export type ClientToServerEventPayloadMap =
+  & LobbyClientToServerEventPayloadMap
+  & GameClientToServerEventPayloadMap;
 
 /** サーバーからクライアントへ送信するイベントごとのペイロード対応表 */
-export type ServerToClientEventPayloadMap = {
-  [SocketEvents.ROOM_JOIN_REJECTED]: RoomJoinRejectedPayload;
-  [SocketEvents.ROOM_UPDATE]: RoomUpdatePayload;
-  [SocketEvents.GAME_START]: GameStartPayload;
-  [SocketEvents.CURRENT_PLAYERS]: CurrentPlayersPayload;
-  [SocketEvents.NEW_PLAYER]: NewPlayerPayload;
-  [SocketEvents.UPDATE_PLAYERS]: UpdatePlayersPayload;
-  [SocketEvents.REMOVE_PLAYER]: RemovePlayerPayload;
-  [SocketEvents.UPDATE_MAP_CELLS]: UpdateMapCellsPayload;
-  [SocketEvents.BOMB_PLACED]: BombPlacedPayload;
-  [SocketEvents.PONG]: PongPayload;
-  [SocketEvents.GAME_END]: undefined;
-  [SocketEvents.GAME_RESULT]: GameResultPayload;
-};
+export type ServerToClientEventPayloadMap =
+  & LobbyServerToClientEventPayloadMap
+  & GameServerToClientEventPayloadMap;
 
 /** 接続ライフサイクルイベントのペイロード型を取得するユーティリティ */
 export type ConnectionLifecyclePayloadOf<TEvent extends keyof ConnectionLifecycleEventPayloadMap> =
diff --git a/packages/shared/src/protocol/maps/commonEventPayloadMap.ts b/packages/shared/src/protocol/maps/commonEventPayloadMap.ts
new file mode 100644
index 0000000..af43c71
--- /dev/null
+++ b/packages/shared/src/protocol/maps/commonEventPayloadMap.ts
@@ -0,0 +1,12 @@
+/**
+ * commonEventPayloadMap
+ * 接続ライフサイクルイベントのペイロード対応表を定義する
+ * CONNECT と DISCONNECT の契約を集約する
+ */
+import { SocketEvents } from "../socketEvents";
+
+/** 接続ライフサイクルイベントのペイロード対応表 */
+export type ConnectionLifecycleEventPayloadMap = {
+  [SocketEvents.CONNECT]: undefined;
+  [SocketEvents.DISCONNECT]: undefined;
+};
diff --git a/packages/shared/src/protocol/maps/gameEventPayloadMap.ts b/packages/shared/src/protocol/maps/gameEventPayloadMap.ts
new file mode 100644
index 0000000..9504411
--- /dev/null
+++ b/packages/shared/src/protocol/maps/gameEventPayloadMap.ts
@@ -0,0 +1,42 @@
+/**
+ * gameEventPayloadMap
+ * ゲーム関連イベントのペイロード対応表を定義する
+ * 開始進行終了，入力，同期の契約を集約する
+ */
+import { SocketEvents } from "../socketEvents";
+import type {
+  BombPlacedPayload,
+  CurrentPlayersPayload,
+  GameResultPayload,
+  GameStartPayload,
+  MovePayload,
+  NewPlayerPayload,
+  PingPayload,
+  PongPayload,
+  RemovePlayerPayload,
+  UpdateMapCellsPayload,
+  UpdatePlayersPayload,
+} from "../eventPayloads";
+
+/** ゲーム関連のクライアント送信イベントペイロード対応表 */
+export type GameClientToServerEventPayloadMap = {
+  [SocketEvents.START_GAME]: undefined;
+  [SocketEvents.READY_FOR_GAME]: undefined;
+  [SocketEvents.MOVE]: MovePayload;
+  [SocketEvents.PLACE_BOMB]: BombPlacedPayload;
+  [SocketEvents.PING]: PingPayload;
+};
+
+/** ゲーム関連のサーバー送信イベントペイロード対応表 */
+export type GameServerToClientEventPayloadMap = {
+  [SocketEvents.GAME_START]: GameStartPayload;
+  [SocketEvents.CURRENT_PLAYERS]: CurrentPlayersPayload;
+  [SocketEvents.NEW_PLAYER]: NewPlayerPayload;
+  [SocketEvents.UPDATE_PLAYERS]: UpdatePlayersPayload;
+  [SocketEvents.REMOVE_PLAYER]: RemovePlayerPayload;
+  [SocketEvents.UPDATE_MAP_CELLS]: UpdateMapCellsPayload;
+  [SocketEvents.BOMB_PLACED]: BombPlacedPayload;
+  [SocketEvents.PONG]: PongPayload;
+  [SocketEvents.GAME_END]: undefined;
+  [SocketEvents.GAME_RESULT]: GameResultPayload;
+};
diff --git a/packages/shared/src/protocol/maps/lobbyEventPayloadMap.ts b/packages/shared/src/protocol/maps/lobbyEventPayloadMap.ts
new file mode 100644
index 0000000..796ff47
--- /dev/null
+++ b/packages/shared/src/protocol/maps/lobbyEventPayloadMap.ts
@@ -0,0 +1,22 @@
+/**
+ * lobbyEventPayloadMap
+ * ロビー関連イベントのペイロード対応表を定義する
+ * ルーム参加要求と拒否通知，ルーム更新契約を集約する
+ */
+import { SocketEvents } from "../socketEvents";
+import type {
+  JoinRoomPayload,
+  RoomJoinRejectedPayload,
+  RoomUpdatePayload,
+} from "../eventPayloads";
+
+/** ロビー関連のクライアント送信イベントペイロード対応表 */
+export type LobbyClientToServerEventPayloadMap = {
+  [SocketEvents.JOIN_ROOM]: JoinRoomPayload;
+};
+
+/** ロビー関連のサーバー送信イベントペイロード対応表 */
+export type LobbyServerToClientEventPayloadMap = {
+  [SocketEvents.ROOM_JOIN_REJECTED]: RoomJoinRejectedPayload;
+  [SocketEvents.ROOM_UPDATE]: RoomUpdatePayload;
+};