diff --git a/app/src/main/java/org/ntlab/radishforandroidstudio/cactusClient/MainActivity.java b/app/src/main/java/org/ntlab/radishforandroidstudio/cactusClient/MainActivity.java
index 0649149..5a655c5 100644
--- a/app/src/main/java/org/ntlab/radishforandroidstudio/cactusClient/MainActivity.java
+++ b/app/src/main/java/org/ntlab/radishforandroidstudio/cactusClient/MainActivity.java
@@ -9,30 +9,49 @@
 import org.ntlab.radishforandroidstudio.cactusClient.views.PlayerFragment;
 import org.ntlab.radishforandroidstudio.cactusClient.views.StartFragment;
 
+/**
+ * Cactusのメインアプリケーション
+ */
 
 public class MainActivity extends AppCompatActivity {
 
     @Override
     protected void onCreate(Bundle savedInstanceState) {
         super.onCreate(savedInstanceState);
-        //splash
-        // ここで5秒間スリープし、スプラッシュを表示させたままにする。
+
+        splash();
+
+        //fragmentの設定
+        Fragment fragment = new StartFragment();
+        addFragment(R.id.fragment_place, fragment, "StartFragment");
+        setContentView(R.layout.activity_main);
+    }
+
+
+    public void splash() {
+        //3秒間スリープし、スプラッシュを表示。
         try {
             Thread.sleep(3000);
         } catch (InterruptedException e) {
             e.printStackTrace();
         }
-
         setTheme(R.style.AppTheme_NoActionBar);
         setContentView(R.layout.activity_main);
-
-        //fragmentの設定
-        Fragment fragment;
-        fragment = new StartFragment();
-        getSupportFragmentManager().beginTransaction().add(R.id.fragment_place, fragment).commit();
-        setContentView(R.layout.activity_main);
     }
 
+    protected void addFragment(int containerViewId, Fragment fragment, String tag) {
+        getSupportFragmentManager().beginTransaction().add(containerViewId, fragment, tag).commit();
+    }
+
+    protected void replaceFragment(int containerViewId, Fragment fragment, String tag, boolean flag) {
+        if (flag) {
+            getSupportFragmentManager().beginTransaction().replace(containerViewId, fragment, tag).addToBackStack(null).commit();
+        } else {
+            getSupportFragmentManager().beginTransaction().replace(containerViewId, fragment, tag).commit();
+        }
+    }
+
+
     @Override
     public void onBackPressed() {
         FragmentManager manager = getSupportFragmentManager();
@@ -48,7 +67,6 @@
         if (fragment instanceof PlayerFragment) {
             manager.beginTransaction().remove(fragment).commit();
             manager.popBackStack();
-//            super.onBackPressed();
             return;
         }
         super.onBackPressed();