diff --git a/utils/downloader.py b/utils/downloader.py
index c539ea0..b5ef163 100644
--- a/utils/downloader.py
+++ b/utils/downloader.py
@@ -80,7 +80,7 @@ def download_images(image_urls, dst_dir, file_prefix="img", concurrency=50, time
     :param concurrency: number of requests process simultaneously
     :return: none
     """
-    concurrency = int(image_urls)
+    concurrency = len(image_urls)
     with concurrent.futures.ThreadPoolExecutor(max_workers=concurrency) as executor:
         future_list = list()
         count = 0