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 455723a..dbfa5ac 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
@@ -4,6 +4,7 @@
 
 import androidx.annotation.NonNull;
 import androidx.lifecycle.MutableLiveData;
+import androidx.recyclerview.widget.SortedList;
 
 import com.example.tampopo_client.models.Activity;
 import com.example.tampopo_client.resources.ActivitiesResource;
@@ -110,11 +111,13 @@
 
             // 自分のフレンドの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()) {
+                List<String> friendUserIds = friendUserIdsLiveData.getValue();
+                for (String userId : friendUserIds) {
                     pullLatestActivity(userId, activitiesResource, new ActivityFetchCallback() {
                         @Override
                         public void onSuccess(Activity activity) {
                             updateFriendToActivitiesLiveData(activity, userId);
+                            sortFriendsByUpdateTime(friendUserIds);
                         }
 
                         @Override
@@ -267,22 +270,9 @@
                     List<String> friendUserIds = friendUserIdsLiveData.getValue();
                     if (friendUserIds == null || !friendUserIds.equals(response.body())) {
                         friendUserIdsLiveData.postValue(response.body());
-                        SortedSet<Friend> friends = new TreeSet<>(new Friend.UpdateTimeComparator());
 
                         assert friendUserIds != null;
-                        friendUserIds.forEach(userId -> {
-                            List<Activity> activities = getActivitiesLiveDataFromUserId(userId).getValue();
-                            if (activities == null || activities.isEmpty()) {
-                                return;
-                            }
-
-                            Activity latestActivity = activities.get(0);
-                            friends.add(new Friend(userId, latestActivity.getUpdateTime()));
-                        });
-
-                        // 並び替えたフレンドのユーザーIDを順番に格納して更新する
-                        sortedFriendUserIds.clear();
-                        friends.forEach(friend -> sortedFriendUserIds.add(friend.getUserId()));
+                        sortFriendsByUpdateTime(friendUserIds);
                     }
                 }
             }
@@ -294,6 +284,29 @@
         });
     }
 
+    /**
+     * ユーザのフレンドのリストを更新順で並び替える
+     *
+     * @param friendUserIds 自身のフレンドのユーザーIDのリスト
+     */
+    private void sortFriendsByUpdateTime(List<String> friendUserIds) {
+        SortedSet<Friend> friends = new TreeSet<>(new Friend.UpdateTimeComparator());
+
+        friendUserIds.forEach(userId -> {
+            List<Activity> activities = getActivitiesLiveDataFromUserId(userId).getValue();
+            if (activities == null || activities.isEmpty()) {
+                return;
+            }
+
+            Activity latestActivity = activities.get(0);
+            friends.add(new Friend(userId, latestActivity.getUpdateTime()));
+        });
+
+        // 並び替えたフレンドのユーザーIDを順番に格納して更新する
+        sortedFriendUserIds.clear();
+        friends.forEach(friend -> sortedFriendUserIds.add(friend.getUserId()));
+    }
+
     public MutableLiveData<Activity> getMyLatestActivityLiveData() {
         return myLatestActivityLiveData;
     }
@@ -311,6 +324,10 @@
         return friendToActivitiesLiveData.get(userId);
     }
 
+    public Map<String, MutableLiveData<List<Activity>>> getFriendToActivitiesLiveData() {
+        return friendToActivitiesLiveData;
+    }
+
     public MutableLiveData<List<String>> getFriendUserIdsLiveData() {
         return friendUserIdsLiveData;
     }
@@ -355,7 +372,7 @@
         public static class UpdateTimeComparator implements Comparator<Friend> {
             @Override
             public int compare(Friend o1, Friend o2) {
-                return o1.getLatestUpdateTime().compareTo(o2.getLatestUpdateTime());
+                return o2.getLatestUpdateTime().compareTo(o1.getLatestUpdateTime());
             }
         }
     }