diff --git a/scrapy/extensions/feedexport.py b/scrapy/extensions/feedexport.py
index 0df32083f..da1a88299 100644
--- a/scrapy/extensions/feedexport.py
+++ b/scrapy/extensions/feedexport.py
@@ -385,6 +385,7 @@ class FeedExporter:
     def _close_slot(self, slot, spider):
         def get_file(slot_):
             if isinstance(slot_.file, PostProcessingManager):
+                slot_.file.close()
                 return slot_.file.file
             return slot_.file