diff --git a/app/src/main/java/com/example/tampopo_client/viewmodels/ActivityViewModel.java b/app/src/main/java/com/example/tampopo_client/viewmodels/ActivityViewModel.java
index 31b884f..2c455f2 100644
--- a/app/src/main/java/com/example/tampopo_client/viewmodels/ActivityViewModel.java
+++ b/app/src/main/java/com/example/tampopo_client/viewmodels/ActivityViewModel.java
@@ -9,7 +9,6 @@
 import com.example.tampopo_client.resources.ActivitiesResource;
 import com.example.tampopo_client.resources.UserResource;
 
-import java.util.HashMap;
 import java.util.List;
 import java.util.Map;
 
@@ -19,8 +18,6 @@
 import retrofit2.Retrofit;
 import retrofit2.converter.jackson.JacksonConverterFactory;
 
-// NOTE: MainActivityでLiveDataをobserveし表示する
-
 /**
  * アクティビティを扱うためのViewModel
  *
@@ -31,8 +28,9 @@
     private final ActivitiesResource activitiesResource;
     private final UserResource userResource;
 
-    private final MutableLiveData<Map<String, Activity>> activitiesLiveData; // key=userId, value=activity
-    private final MutableLiveData<List<String>> friendUserIdsLiveData;
+    private final Map<String, MutableLiveData<List<Activity>>> friendToActivitiesLiveData; // key=userId
+    private final MutableLiveData<List<String>> friendUserIdsLiveData; // フレンドのユーザーIDのリスト
+    private final MutableLiveData<Activity> myLatestActivityLiveData; // 自分の最新のアクティビティ
 
     private final String userId;
     private final String token;
@@ -42,29 +40,26 @@
         this.token = token;
 
         // Retrofitの初期化
-        final Retrofit retrofit = new Retrofit.Builder()
-                .baseUrl("http://nitta-lab-www.is.konan-u.ac.jp/tampopo/")
-                .addConverterFactory(JacksonConverterFactory.create())
-                .build();
+        final Retrofit retrofit = new Retrofit.Builder().baseUrl("http://nitta-lab-www.is.konan-u.ac.jp/tampopo/").addConverterFactory(JacksonConverterFactory.create()).build();
         activitiesResource = retrofit.create(ActivitiesResource.class);
         userResource = retrofit.create(UserResource.class);
 
-        // LiveDataの初期化
-        activitiesLiveData = new MutableLiveData<>(Map.of());
+        friendToActivitiesLiveData = Map.of();
         friendUserIdsLiveData = new MutableLiveData<>(List.of());
+        myLatestActivityLiveData = new MutableLiveData<>();
     }
 
     @Override
     public Runnable onUpdate() {
         return () -> {
-            if (activitiesLiveData == null || friendUserIdsLiveData == null) {
+            if (friendToActivitiesLiveData == null || friendUserIdsLiveData == null || myLatestActivityLiveData == null) {
                 return;
             }
 
             // 最新のアクティビティを取得して更新する
             if (friendUserIdsLiveData.isInitialized() && friendUserIdsLiveData.getValue() != null) {
                 for (String userId : friendUserIdsLiveData.getValue()) {
-                    pullLatestActivity(userId);
+                    pullLatestActivity(userId, activitiesResource, friendToActivitiesLiveData);
                 }
             }
 
@@ -79,6 +74,10 @@
     }
 
     public void createActivity(String userId, String token, String newActivity) {
+        if (!myLatestActivityLiveData.isInitialized()) {
+            return;
+        }
+
         Call<String> createActivityCall = activitiesResource.addActivity(userId, token, newActivity);
         createActivityCall.enqueue(new Callback<String>() {
             @Override
@@ -86,24 +85,16 @@
                 if (response.isSuccessful()) {
                     String createdActivityId = response.body();
 
-                    // TODO: 仮作成なので改善必須
+                    // TODO: 仮作成なので改善したい
                     Call<Activity> getActivityCall = activitiesResource.getActivity(userId, createdActivityId);
                     getActivityCall.enqueue(new Callback<Activity>() {
                         @Override
                         public void onResponse(@NonNull Call<Activity> call, @NonNull Response<Activity> response) {
-                            Map<String, Activity> activities = activitiesLiveData.getValue();
-                            if (activities == null) {
-                                activities = new HashMap<>();
-                            }
-
                             Activity createdActivity = response.body();
-                            if (activities.containsKey(userId)) {
-                                activities.replace(userId, createdActivity);
-                            } else {
-                                activities.put(userId, createdActivity);
+                            if (createdActivity == null) {
+                                return;
                             }
-
-                            activitiesLiveData.postValue(activities);
+                            myLatestActivityLiveData.postValue(createdActivity);
                         }
 
                         @Override
@@ -126,28 +117,42 @@
     /**
      * 最新のユーザーのアクティビティを取得・更新する
      *
-     * @param userId 取得対象のユーザーのID
+     * @param userId                     取得対象のユーザーのID
+     * @param resource                   アクティビティのリソース
+     * @param friendToActivitiesLiveData フレンドのユーザーIDからアクティビティへの写像のライブデータ
      */
-    private void pullLatestActivity(String userId) {
-        Call<List<Activity>> fetchActivityCall = activitiesResource.getActivities(userId, "LATEST");
+    private void pullLatestActivity(String userId, ActivitiesResource resource, Map<String, MutableLiveData<List<Activity>>> friendToActivitiesLiveData) {
+        Call<List<Activity>> fetchActivityCall = resource.getActivities(userId, "LATEST");
         fetchActivityCall.enqueue(new Callback<List<Activity>>() {
             @Override
             public void onResponse(@NonNull Call<List<Activity>> call, @NonNull Response<List<Activity>> response) {
                 if (response.isSuccessful()) {
-                    List<Activity> fetchedActivities = response.body();
-                    if (fetchedActivities != null) {
-                        Activity latestActivity = response.body().get(0);
-                        Map<String, Activity> activities = activitiesLiveData.getValue();
-                        if (activities == null) {
-                            activities = new HashMap<>();
-                        }
-                        if (activities.containsKey(userId)) {
-                            activities.replace(userId, latestActivity);
-                        } else {
-                            activities.put(userId, latestActivity);
-                        }
+                    List<Activity> fetchedActivities = response.body(); // アクティビティが存在しない場合は空のリスト
+                    if (fetchedActivities == null) {
+                        return;
+                    }
 
-                        activitiesLiveData.postValue(activities);
+                    if (friendToActivitiesLiveData.get(userId) == null) {
+                        friendToActivitiesLiveData.put(userId, new MutableLiveData<>(List.of()));
+                    }
+                    MutableLiveData<List<Activity>> userActivitiesLiveData = friendToActivitiesLiveData.get(userId);
+                    assert userActivitiesLiveData != null;
+
+                    List<Activity> userActivities = userActivitiesLiveData.getValue();
+                    if (userActivities == null) {
+                        return;
+                    }
+                    if (fetchedActivities.isEmpty()) {
+                        return;
+                    }
+
+                    if (userActivities.isEmpty()) {
+                        userActivitiesLiveData.postValue(fetchedActivities);
+                    } else {
+                        if (userActivities.equals(fetchedActivities)) {
+                            return;
+                        }
+                        userActivitiesLiveData.postValue(fetchedActivities);
                     }
                 }
             }
@@ -182,8 +187,12 @@
         });
     }
 
-    public MutableLiveData<Map<String, Activity>> getActivitiesLiveData() {
-        return activitiesLiveData;
+    public MutableLiveData<Activity> getMyLatestActivityLiveData() {
+        return myLatestActivityLiveData;
+    }
+
+    public MutableLiveData<List<Activity>> getActivitiesLiveDataFromUserId(String userId) {
+        return friendToActivitiesLiveData.get(userId);
     }
 
     public MutableLiveData<List<String>> getFriendUserIdsLiveData() {