diff --git a/app/src/main/java/com/example/sprout/refactor/activity/RoomListActivity.java b/app/src/main/java/com/example/sprout/refactor/activity/RoomListActivity.java
index 00c00eb..1b901eb 100644
--- a/app/src/main/java/com/example/sprout/refactor/activity/RoomListActivity.java
+++ b/app/src/main/java/com/example/sprout/refactor/activity/RoomListActivity.java
@@ -1,16 +1,11 @@
 package com.example.sprout.refactor.activity;
 
-import android.content.Intent;
 import android.databinding.DataBindingUtil;
 import android.os.Bundle;
-import android.support.v7.app.AppCompatActivity;
-import android.widget.Toast;
 
 import com.example.sprout.R;
 import com.example.sprout.databinding.RfActivityRoomListBinding;
 import com.example.sprout.refactor.adapter.RoomListAdapter;
-import com.example.sprout.refactor.common.ActivityEvent;
-import com.example.sprout.refactor.contract.ViewContract;
 import com.example.sprout.refactor.viewmodel.RoomListViewModel;
 
 /**
@@ -18,44 +13,29 @@
  *
  * @author matsumoto_k
  */
-public class RoomListActivity extends AppCompatActivity implements ViewContract {
+public class RoomListActivity extends BaseActivity {
+
+    private RoomListViewModel roomMainViewModel = null;
+    private RfActivityRoomListBinding binding = null;
 
     @Override
     protected void onCreate(Bundle savedInstanceState) {
         super.onCreate(savedInstanceState);
-        RfActivityRoomListBinding binding = DataBindingUtil.setContentView(this, R.layout.rf_activity_room_list);
-        RoomListViewModel roomMainViewModel = new RoomListViewModel(new RoomListAdapter(this), (ViewContract) this);
+        binding = DataBindingUtil.setContentView(this, R.layout.rf_activity_room_list);
+        roomMainViewModel = new RoomListViewModel(new RoomListAdapter(this));
         binding.setViewModel(roomMainViewModel);
         getLifecycle().addObserver(roomMainViewModel);
     }
 
     @Override
-    public void startActivity(ActivityEvent event) {
-        switch (event) {
-            case CREATE_ROOM:
-                startActivity(new Intent(RoomListActivity.this, RoomCreateActivity.class));
-                break;
-            case ROOM_MAIN:
-                startActivity(new Intent(RoomListActivity.this, RoomMainActivity.class));
-                break;
-            case INPUT_KEY:
-                startActivity(new Intent(RoomListActivity.this, RoomInputKeyActivity.class));
-                break;
-        }
+    protected void onResume() {
+        super.onResume();
+        addUiObserver(roomMainViewModel);
     }
 
     @Override
-    public void finishActivity() {
-
-    }
-
-    @Override
-    public void showShortToast(String message) {
-        Toast.makeText(this, message, Toast.LENGTH_SHORT).show();
-    }
-
-    @Override
-    public void showLongToast(String message) {
-        Toast.makeText(this, message, Toast.LENGTH_LONG).show();
+    protected void onPause() {
+        super.onPause();
+        removeUiObserver(roomMainViewModel);
     }
 }
diff --git a/app/src/main/java/com/example/sprout/refactor/viewmodel/RoomListViewModel.java b/app/src/main/java/com/example/sprout/refactor/viewmodel/RoomListViewModel.java
index 6788372..9a75f5f 100644
--- a/app/src/main/java/com/example/sprout/refactor/viewmodel/RoomListViewModel.java
+++ b/app/src/main/java/com/example/sprout/refactor/viewmodel/RoomListViewModel.java
@@ -6,9 +6,12 @@
 import android.support.v7.widget.RecyclerView;
 import android.widget.LinearLayout;
 
+import com.example.sprout.refactor.activity.RoomCreateActivity;
+import com.example.sprout.refactor.activity.RoomInputKeyActivity;
+import com.example.sprout.refactor.activity.RoomMainActivity;
 import com.example.sprout.refactor.adapter.RoomListAdapter;
-import com.example.sprout.refactor.common.ActivityEvent;
-import com.example.sprout.refactor.contract.ViewContract;
+import com.example.sprout.refactor.messengers.NavigationMessage;
+import com.example.sprout.refactor.messengers.ToastMessage;
 import com.example.sprout.refactor.model.ModelLocator;
 import com.example.sprout.refactor.model.entity.Room;
 import com.example.sprout.refactor.model.entity.RoomResponse;
@@ -29,19 +32,17 @@
 
     private RoomRepository roomRepository = null;
     private RoomListAdapter adapter = null;
-    private ViewContract viewContract = null;
     private RoomListAdapter.OnItemClickedListener listener = null;
     private Observer<Rooms> roomListObserver = null;
     private Observer<RoomResponse> enterRoomObserver = null;
 
-    public RoomListViewModel(RoomListAdapter adapter, ViewContract viewContract) {
+    public RoomListViewModel(RoomListAdapter adapter) {
         this.roomRepository = ModelLocator.getModel(ModelLocator.Tag.ROOM_REPOSITORY, RoomRepository.class);
-        this.viewContract = viewContract;
 
         this.listener = room -> {
             if (room.hasKey()) {
                 PreferenceUtil.getInstance().saveInt(PreferenceUtil.Key.ROOM_ID, room.getRoomId());
-                viewContract.startActivity(ActivityEvent.INPUT_KEY);
+                navigationObservable.notifyObservers(new NavigationMessage(NavigationMessage.Type.Start, RoomInputKeyActivity.class));
             } else {
                 roomRepository.enterRoom(room.getRoomId(), PreferenceUtil.getInstance().getInt(PreferenceUtil.Key.USER_ID));
             }
@@ -71,15 +72,15 @@
                     ModelLocator.setModel(ModelLocator.Tag.RoomResponse, roomResponse);
                     PreferenceUtil.getInstance().saveInt(PreferenceUtil.Key.ROOM_ID, roomResponse.getRoom().getRoomId());
                     PreferenceUtil.getInstance().saveInt(PreferenceUtil.Key.MEMBER_ID, roomResponse.getMemberId());
-                    viewContract.startActivity(ActivityEvent.ROOM_MAIN);
+                    navigationObservable.notifyObservers(new NavigationMessage(NavigationMessage.Type.Start, RoomMainActivity.class));
                 } else {
-                    viewContract.showShortToast("入室に失敗しました");
+                    toastObservable.notifyObservers(new ToastMessage("入室に失敗しました", ToastMessage.Length.SHORT));
                 }
             }
 
             @Override
             public void error(Throwable throwable) {
-                viewContract.showShortToast("入室に失敗しました");
+                toastObservable.notifyObservers(new ToastMessage("入室に失敗しました", ToastMessage.Length.SHORT));
             }
         };
     }
@@ -104,7 +105,7 @@
     }
 
     public void onClickCreateRoom() {
-        viewContract.startActivity(ActivityEvent.CREATE_ROOM);
+        navigationObservable.notifyObservers(new NavigationMessage(NavigationMessage.Type.Start, RoomCreateActivity.class));
     }
 
     @BindingAdapter("setRoomListAdapter")