diff --git a/app/src/main/kotlin/jackall/overlaymulticounter/vo/Counter.kt b/app/src/main/kotlin/jackall/overlaymulticounter/vo/Counter.kt
index ea2d6ea..3af3c90 100644
--- a/app/src/main/kotlin/jackall/overlaymulticounter/vo/Counter.kt
+++ b/app/src/main/kotlin/jackall/overlaymulticounter/vo/Counter.kt
@@ -1,12 +1,15 @@
 package jackall.overlaymulticounter.vo
 
 import io.realm.RealmObject
+import io.realm.annotations.PrimaryKey
 import java.util.*
 
 /**
  * Created by matsumoto_k on 2017/11/08.
  */
 open class Counter(
+        @PrimaryKey
+        open var id: Int = 0,
         open var title: String = "",
         open var count: Int = 0,
         open var createAt: Date = Date()