diff --git a/app/src/main/kotlin/jackall/moncalc/utils/RuntimePermissionUtil.kt b/app/src/main/kotlin/jackall/moncalc/utils/RuntimePermissionUtil.kt
new file mode 100644
index 0000000..aaaa03d
--- /dev/null
+++ b/app/src/main/kotlin/jackall/moncalc/utils/RuntimePermissionUtil.kt
@@ -0,0 +1,21 @@
+package jackall.moncalc.utils
+
+import android.content.Context
+import android.os.Build
+import android.provider.Settings
+
+
+/**
+ * Created by matsumoto_k on 2017/11/06.
+ */
+class RuntimePermissionUtil {
+
+    companion object {
+        fun checkOverlayPermission(context: Context): Boolean {
+            if (Build.VERSION.SDK_INT < 23) {
+                return true
+            }
+            return Settings.canDrawOverlays(context)
+        }
+    }
+}
diff --git a/app/src/main/kotlin/jackall/moncalc/viewmodel/MainViewModel.kt b/app/src/main/kotlin/jackall/moncalc/viewmodel/MainViewModel.kt
index cb13575..0c4d3d1 100644
--- a/app/src/main/kotlin/jackall/moncalc/viewmodel/MainViewModel.kt
+++ b/app/src/main/kotlin/jackall/moncalc/viewmodel/MainViewModel.kt
@@ -1,49 +1,66 @@
 package jackall.moncalc.viewmodel
 
+import android.app.Activity
+import android.app.AlertDialog
 import android.arch.lifecycle.ViewModel
 import android.arch.lifecycle.ViewModelProvider
-import android.content.Context
+import android.content.DialogInterface
 import android.content.Intent
 import android.databinding.ObservableField
+import android.net.Uri
+import android.provider.Settings
 import android.view.View
 import jackall.moncalc.R
 import jackall.moncalc.service.MainService
+import jackall.moncalc.utils.RuntimePermissionUtil
 import jackall.moncalc.utils.ServiceUtil.Companion.isMainServiceRunning
 
+
 /**
  * MainActivityのViewModel.
  *
  * Created by matsumoto_k on 2017/11/01.
  */
-class MainViewModel(val context: Context) : LifecycleViewModel() {
+class MainViewModel(val activity: Activity) : LifecycleViewModel() {
     val serviceButtonText = ObservableField<String>("")
     val serviceIntent by lazy {
-        val intent = Intent(context, MainService::class.java)
+        val intent = Intent(activity, MainService::class.java)
         intent.flags = Intent.FLAG_ACTIVITY_NEW_TASK
         intent
     }
 
     init {
-        if (isMainServiceRunning(context)) {
-            serviceButtonText.set(context.resources.getString(R.string.stop_service))
+        if (isMainServiceRunning(activity)) {
+            serviceButtonText.set(activity.resources.getString(R.string.stop_service))
         } else {
-            serviceButtonText.set(context.resources.getString(R.string.start_service))
+            serviceButtonText.set(activity.resources.getString(R.string.start_service))
         }
     }
 
-    class Factory(val context: Context) : ViewModelProvider.NewInstanceFactory() {
+    class Factory(val context: Activity) : ViewModelProvider.NewInstanceFactory() {
         override fun <T : ViewModel?> create(modelClass: Class<T>): T {
             return MainViewModel(context) as T
         }
     }
 
     fun onClickServiceButton(view: View) {
-        if (!isMainServiceRunning(context)) {
-            context.startService(serviceIntent)
-            serviceButtonText.set(context.resources.getString(R.string.stop_service))
+        if (RuntimePermissionUtil.checkOverlayPermission(activity)) {
+            if (!isMainServiceRunning(activity)) {
+                activity.startService(serviceIntent)
+                serviceButtonText.set(activity.resources.getString(R.string.stop_service))
+            } else {
+                activity.stopService(serviceIntent)
+                serviceButtonText.set(activity.resources.getString(R.string.start_service))
+            }
         } else {
-            context.stopService(serviceIntent)
-            serviceButtonText.set(context.resources.getString(R.string.start_service))
+            AlertDialog.Builder(activity)
+                    .setMessage("常駐機能を使用するには権限の許可が必要です。")
+                    .setPositiveButton("設定", DialogInterface.OnClickListener { dialog, which ->
+                        val intent = Intent(Settings.ACTION_MANAGE_OVERLAY_PERMISSION, Uri.parse("package:jackall.moncalc"))
+                        activity.startActivityForResult(intent, 2)
+                    })
+                    .setNegativeButton("許可しない", null)
+                    .show()
         }
     }
 }
\ No newline at end of file