diff --git a/app/services/spreadsheet/judge.rb b/app/services/spreadsheet/judge.rb
index ea373162..eada2f3f 100644
--- a/app/services/spreadsheet/judge.rb
+++ b/app/services/spreadsheet/judge.rb
@@ -32,7 +32,7 @@ def build
             sheet.merge_cells "#{sum_column}1:#{sum_column}2"
             sheet.merge_cells "#{place_column}1:#{place_column}2"
 
-            generate_data_rows(grade).each { |row| sheet.add_row row, style: data_style }
+            generate_data_rows(grade.id).each { |row| sheet.add_row row, style: data_style }
 
             # Set only after all data, otherwise will be ignored
             sheet.column_widths *column_widths