diff --git a/src/cloudforet/cost_analysis/connector/azure_cost_mgmt_connector.py b/src/cloudforet/cost_analysis/connector/azure_cost_mgmt_connector.py
index f4c8642..a8b8118 100644
--- a/src/cloudforet/cost_analysis/connector/azure_cost_mgmt_connector.py
+++ b/src/cloudforet/cost_analysis/connector/azure_cost_mgmt_connector.py
@@ -117,7 +117,7 @@ def get_cost_data(self, blobs: list, options: dict) -> list:
                 costs_data = df.to_dict("records")
                 total_cost_count += len(costs_data)
                 yield costs_data
-
+            del df_chunk
             del cost_csv
         _LOGGER.debug(f"[get_cost_data] total_cost_count: {total_cost_count}")