diff --git a/app/controllers/entry_sheet_controller.rb b/app/controllers/entry_sheet_controller.rb
index 080d66a69..316272d00 100644
--- a/app/controllers/entry_sheet_controller.rb
+++ b/app/controllers/entry_sheet_controller.rb
@@ -7,7 +7,7 @@ def show
     object = JSON.parse(decrypted)
 
     @profile = Profile.find(object['profile_id'])
-    @speaker = Speaker.find(object['speaker_id'])
+    @speaker = object['speaker_id'].present? ? Speaker.find(object['speaker_id']) : nil
     @conference = Conference.find_by(abbr: params[:event])
 
     # 全てのテーブルの行数を取得