diff --git a/apps/server/src/domains/room/application/ports/roomUseCasePorts.ts b/apps/server/src/domains/room/application/ports/roomUseCasePorts.ts
index b00b3c8..c381914 100644
--- a/apps/server/src/domains/room/application/ports/roomUseCasePorts.ts
+++ b/apps/server/src/domains/room/application/ports/roomUseCasePorts.ts
@@ -10,6 +10,12 @@
   status: "joined" | "duplicate" | "full";
 };
 
+/** ルームユースケースが利用する出力ポート */
+export interface RoomOutputPort {
+  publishRoomUpdate(roomId: roomTypes.Room["roomId"], room: roomTypes.Room): void;
+  publishJoinRejected(payload: roomTypes.JoinRoomRejectedPayload): void;
+}
+
 /** ルーム参加ユースケースが利用する参加操作ポート */
 export interface JoinRoomPort {
   addPlayerToRoom(roomId: string, socketId: string, playerName: string): JoinRoomResult;
diff --git a/apps/server/src/domains/room/application/useCases/joinRoomUseCase.ts b/apps/server/src/domains/room/application/useCases/joinRoomUseCase.ts
index ecca7bd..406bc68 100644
--- a/apps/server/src/domains/room/application/useCases/joinRoomUseCase.ts
+++ b/apps/server/src/domains/room/application/useCases/joinRoomUseCase.ts
@@ -3,14 +3,18 @@
  * ルーム参加要求を処理し，状態更新を配信するユースケース
  */
 import type { roomTypes } from "@repo/shared";
-import type { JoinRoomPort, JoinRoomResult } from "../ports/roomUseCasePorts";
+import type {
+  JoinRoomPort,
+  JoinRoomResult,
+  RoomOutputPort,
+} from "../ports/roomUseCasePorts";
 import { logEvent } from "@server/logging/logEvent";
 
 type JoinRoomUseCaseParams = {
   roomManager: JoinRoomPort;
   socketId: string;
   data: roomTypes.JoinRoomPayload;
-  publishRoomUpdate: (roomId: roomTypes.Room["roomId"], room: roomTypes.Room) => void;
+  output: RoomOutputPort;
 };
 
 /** 参加イベントを受け取り，ルーム更新を配信する */
@@ -18,7 +22,7 @@
   roomManager,
   socketId,
   data,
-  publishRoomUpdate,
+  output,
 }: JoinRoomUseCaseParams): JoinRoomResult => {
   const { roomId, playerName } = data;
   logEvent("RoomUseCase", {
@@ -31,6 +35,11 @@
 
   const joinResult = roomManager.addPlayerToRoom(roomId, socketId, playerName);
   if (joinResult.status !== "joined") {
+    output.publishJoinRejected({
+      roomId,
+      reason: joinResult.status,
+    });
+
     logEvent("RoomUseCase", {
       event: "JOIN_ROOM",
       result: "rejected",
@@ -41,7 +50,7 @@
     return joinResult;
   }
 
-  publishRoomUpdate(roomId, joinResult.room);
+  output.publishRoomUpdate(roomId, joinResult.room);
 
   return joinResult;
 };
diff --git a/apps/server/src/domains/room/application/useCases/roomDisconnectUseCase.ts b/apps/server/src/domains/room/application/useCases/roomDisconnectUseCase.ts
index 1f3a4e1..2fe1be0 100644
--- a/apps/server/src/domains/room/application/useCases/roomDisconnectUseCase.ts
+++ b/apps/server/src/domains/room/application/useCases/roomDisconnectUseCase.ts
@@ -3,20 +3,20 @@
  * 切断時のルーム退出処理と状態更新配信を行うユースケース
  */
 import type { DisconnectRoomPort } from "../ports/roomUseCasePorts";
-import type { roomTypes } from "@repo/shared";
+import type { RoomOutputPort } from "../ports/roomUseCasePorts";
 import { logEvent } from "@server/logging/logEvent";
 
 type RoomDisconnectUseCaseParams = {
   roomManager: DisconnectRoomPort;
   socketId: string;
-  publishRoomUpdate: (roomId: roomTypes.Room["roomId"], room: roomTypes.Room) => void;
+  output: Pick<RoomOutputPort, "publishRoomUpdate">;
 };
 
 /** 切断ソケットを各ルームから退出させ，更新ルームを配信する */
 export const roomDisconnectUseCase = ({
   roomManager,
   socketId,
-  publishRoomUpdate,
+  output,
 }: RoomDisconnectUseCaseParams) => {
   const updatedRooms = roomManager.removePlayer(socketId);
   logEvent("RoomUseCase", {
@@ -27,7 +27,7 @@
   });
 
   updatedRooms.forEach((room) => {
-    publishRoomUpdate(room.roomId, room);
+    output.publishRoomUpdate(room.roomId, room);
     logEvent("RoomUseCase", {
       event: "ROOM_UPDATE",
       result: "emitted",
diff --git a/apps/server/src/network/handlers/room/createRoomEventPublisher.ts b/apps/server/src/network/handlers/room/createRoomEventPublisher.ts
index 5e2bf4d..d838bcc 100644
--- a/apps/server/src/network/handlers/room/createRoomEventPublisher.ts
+++ b/apps/server/src/network/handlers/room/createRoomEventPublisher.ts
@@ -6,16 +6,14 @@
 import { protocol } from "@repo/shared";
 import { createEmitToRoom } from "@server/network/adapters/socketEmitters";
 import type { roomTypes } from "@repo/shared";
+import type { RoomOutputPort } from "@server/domains/room/application/ports/roomUseCasePorts";
 import type { CommonHandlerContext } from "../CommonHandler";
 
 type RoomId = roomTypes.Room["roomId"];
 type RoomUpdatePayload = roomTypes.Room;
 
 /** ルーム更新イベントの送信インターフェース */
-export type RoomEventPublisher = {
-  publishRoomUpdate: (roomId: RoomId, room: RoomUpdatePayload) => void;
-  publishJoinRejected: (payload: roomTypes.JoinRoomRejectedPayload) => void;
-};
+export type RoomEventPublisher = RoomOutputPort;
 
 /** 共通送信コンテキストからルームイベント送信関数を生成する */
 export const createRoomEventPublisher = (
@@ -32,15 +30,14 @@
 };
 
 /** 切断時のルーム更新送信関数を生成する */
-export const createRoomDisconnectPublisher = (io: Server): RoomEventPublisher => {
+export const createRoomDisconnectPublisher = (
+  io: Server
+): Pick<RoomOutputPort, "publishRoomUpdate"> => {
   const emitToRoom = createEmitToRoom(io);
 
   return {
     publishRoomUpdate: (roomId: RoomId, room: RoomUpdatePayload) => {
       emitToRoom(roomId, protocol.SocketEvents.ROOM_UPDATE, room);
     },
-    publishJoinRejected: () => {
-      return;
-    },
   };
 };
diff --git a/apps/server/src/network/handlers/room/handleRoomDisconnect.ts b/apps/server/src/network/handlers/room/handleRoomDisconnect.ts
index c711d20..c0f1bd1 100644
--- a/apps/server/src/network/handlers/room/handleRoomDisconnect.ts
+++ b/apps/server/src/network/handlers/room/handleRoomDisconnect.ts
@@ -18,6 +18,6 @@
   roomDisconnectUseCase({
     roomManager,
     socketId: socket.id,
-    publishRoomUpdate: roomDisconnectPublisher.publishRoomUpdate,
+    output: roomDisconnectPublisher,
   });
 };
diff --git a/apps/server/src/network/handlers/room/registerRoomHandlers.ts b/apps/server/src/network/handlers/room/registerRoomHandlers.ts
index d1000ce..ebca36a 100644
--- a/apps/server/src/network/handlers/room/registerRoomHandlers.ts
+++ b/apps/server/src/network/handlers/room/registerRoomHandlers.ts
@@ -5,7 +5,6 @@
 import { Server, Socket } from "socket.io";
 import { RoomManager } from "@server/domains/room/RoomManager";
 import { protocol } from "@repo/shared";
-import type { roomTypes } from "@repo/shared";
 import { joinRoomUseCase } from "@server/domains/room/application/useCases/joinRoomUseCase";
 import { createCommonHandlerContext } from "@server/network/handlers/CommonHandler";
 import { createRoomEventPublisher } from "./createRoomEventPublisher";
@@ -33,24 +32,17 @@
     }
 
     const { roomId } = data;
-    let joinedRoom: roomTypes.Room | null = null;
 
     const joinResult = joinRoomUseCase({
       roomManager,
       socketId: socket.id,
       data,
-      publishRoomUpdate: (_roomId, room) => {
-        joinedRoom = room;
-      },
+      output: roomPublisher,
     });
 
     // 参加拒否時は理由を通知する
     switch (joinResult.status) {
       case "full":
-        roomPublisher.publishJoinRejected({
-          roomId,
-          reason: "full",
-        });
         logEvent("Network", {
           event: "JOIN_ROOM",
           result: "rejected_room_full",
@@ -60,10 +52,6 @@
         return;
 
       case "duplicate":
-        roomPublisher.publishJoinRejected({
-          roomId,
-          reason: "duplicate",
-        });
         logEvent("Network", {
           event: "JOIN_ROOM",
           result: "rejected_duplicate",