diff --git a/ecs/jskult-batch-monthly/src/batch/jskult_batch_monthly.py b/ecs/jskult-batch-monthly/src/batch/jskult_batch_monthly.py
index fe9b46ee..2a8d4c06 100644
--- a/ecs/jskult-batch-monthly/src/batch/jskult_batch_monthly.py
+++ b/ecs/jskult-batch-monthly/src/batch/jskult_batch_monthly.py
@@ -221,6 +221,7 @@ def make_csv_data(record_csv: list, resLog_f):
         # データ部分書き込み
         for record_data in record_csv:
             record_value = list(record_data.values())
+            record_value = ['' if n is None else n for n in record_value]
             csv_data = ",".join(map(str, record_value))
             fp.write(f'{csv_data}\n')