diff --git a/data/src/main/java/one/nem/kidshift/data/ChildData.java b/data/src/main/java/one/nem/kidshift/data/ChildData.java
index c06944b..b23c1b8 100644
--- a/data/src/main/java/one/nem/kidshift/data/ChildData.java
+++ b/data/src/main/java/one/nem/kidshift/data/ChildData.java
@@ -36,4 +36,11 @@ public interface ChildData {
      * @param childId 子ID
      */
     void removeChild(String childId);
+
+    /**
+     * 子ユーザーログインコード発行
+     * @param childId 子ID
+     * @return int ログインコード
+     */
+    int issueLoginCode(String childId);
 }
diff --git a/data/src/main/java/one/nem/kidshift/data/impl/ChildDataDummyImpl.java b/data/src/main/java/one/nem/kidshift/data/impl/ChildDataDummyImpl.java
index 26b9569..310d727 100644
--- a/data/src/main/java/one/nem/kidshift/data/impl/ChildDataDummyImpl.java
+++ b/data/src/main/java/one/nem/kidshift/data/impl/ChildDataDummyImpl.java
@@ -45,4 +45,9 @@ public class ChildDataDummyImpl implements ChildData {
     public void removeChild(String childId) {
 
     }
+
+    @Override
+    public int issueLoginCode(String childId) {
+        return 123456;
+    }
 }