diff --git a/src/main/java/org/ntlab/tampoposerver/models/ChatRooms.java b/src/main/java/org/ntlab/tampoposerver/models/ChatRooms.java
index 542c07d..a5849b5 100644
--- a/src/main/java/org/ntlab/tampoposerver/models/ChatRooms.java
+++ b/src/main/java/org/ntlab/tampoposerver/models/ChatRooms.java
@@ -20,6 +20,9 @@
         this.chatRoomId = chatRoomId;
         this.user0Id = user0Id;
         this.user1Id = user1Id;
+
+        this.users.add(user0Id);
+        this.users.add(user1Id);
     }
 
     public String getUser0Id(){
@@ -81,4 +84,12 @@
         public String getSenderId() { return senderId;}
         public String getContent() { return content;}
     }
+
+    public boolean removeUser(String userId) {
+        return users.remove(userId);
+    }
+
+    public boolean isEmpty() {
+        return users.isEmpty();
+    }
 }
diff --git a/src/main/java/org/ntlab/tampoposerver/repositories/ChatRoomsRepository.java b/src/main/java/org/ntlab/tampoposerver/repositories/ChatRoomsRepository.java
index 3ff56f8..bc06f8a 100644
--- a/src/main/java/org/ntlab/tampoposerver/repositories/ChatRoomsRepository.java
+++ b/src/main/java/org/ntlab/tampoposerver/repositories/ChatRoomsRepository.java
@@ -103,4 +103,5 @@
     public ChatRooms getChatRoom(int chatRoomId) {
         return chatRooms.get(chatRoomId);
     }
+
 }
\ No newline at end of file
diff --git a/src/main/java/org/ntlab/tampoposerver/resources/ChatRoomsResource.java b/src/main/java/org/ntlab/tampoposerver/resources/ChatRoomsResource.java
index f8d92e9..0c01e17 100644
--- a/src/main/java/org/ntlab/tampoposerver/resources/ChatRoomsResource.java
+++ b/src/main/java/org/ntlab/tampoposerver/resources/ChatRoomsResource.java
@@ -157,15 +157,17 @@
 
     //チャットルームの削除
     @DELETE
-    @Path("/{chatroom-id}")
-    public Response deleteChatRoom(@PathParam("chatroom-id") int chatRoomId, @FormParam("user-id") String userId, @QueryParam("token") String token) {
+    @Path("/{chatroom-id}/{user-id}")
+    @Produces(MediaType.APPLICATION_JSON)
+    public Response leaveChatRoom(@PathParam("chatroom-id") int chatRoomId,
+                                  @PathParam("user-id") String userId,
+                                  @QueryParam("token") String token) {
+
         ChatRooms room = chatRoomsRepository.getChatRoom(chatRoomId);
         if (room == null) throw new NotFoundException("チャットルームが存在しません");
 
         User user = userRepository.getUser(userId);
-        if (user == null) {
-            throw new NotFoundException("IDが存在しません");
-        }
+        if (user == null) throw new NotFoundException("ユーザーが存在しません");
 
         if (token == null || !token.equals(user.getToken())) {
             throw new WebApplicationException(
@@ -175,10 +177,19 @@
             );
         }
 
+        boolean removed = room.removeUser(userId);
+        if (!removed) {
+            return Response.status(Response.Status.BAD_REQUEST)
+                    .entity(Map.of("message", "ユーザーはこのルームに存在しません"))
+                    .build();
+        }
 
-        ChatRooms chatRoom = chatRoomsRepository.deleteChatRoom(chatRoomId);
-        return Response.noContent().build();
-        //return Response.status(Response.Status.noContent).entity(chatRoom).build();
+        if (room.isEmpty()) {
+            chatRoomsRepository.deleteChatRoom(chatRoomId);
+            return Response.ok(Map.of("message", "両者が退出したためルームを削除しました")).build();
+        }
+
+        return Response.noContent().build(); // 片方退出
     }