diff --git a/finam/export.py b/finam/export.py
index a4c78a7..195d83a 100644
--- a/finam/export.py
+++ b/finam/export.py
@@ -379,6 +379,6 @@ def download(self,
             if df is None:
                 df = chunk_df
             else:
-                df = df.append(chunk_df)
+                df = df.append(chunk_df, ignore_index=True)
 
         return df