diff --git a/configargparse.py b/configargparse.py
index 46ddbd6..4e718ea 100644
--- a/configargparse.py
+++ b/configargparse.py
@@ -749,7 +749,7 @@ def convert_item_to_command_line_arg(self, action, key, value):
 
             if action is None or isinstance(action, argparse._AppendAction):
                 for list_elem in value:
-                    if accepts_list and isinstance(list_elem, list):
+                    if accepts_list_and_has_nargs and isinstance(list_elem, list):
                         args.append(command_line_key)
                         for sub_elem in list_elem:
                             args.append(str(sub_elem))