diff --git a/app/build.gradle b/app/build.gradle
index 40adf01..dbf7c23 100644
--- a/app/build.gradle
+++ b/app/build.gradle
@@ -27,6 +27,8 @@
     androidTestImplementation 'com.android.support.test.espresso:espresso-core:3.0.2'
     // Retrofit
     implementation "com.squareup.retrofit2:retrofit:2.5.0"
+    //Jackson
+    implementation 'com.squareup.retrofit2:converter-jackson:2.5.0'
     //QRコードリーダー
     implementation 'com.journeyapps:zxing-android-embedded:3.6.0'
     implementation 'com.android.support:design:28.0.0'