diff --git a/Lib/distutils/archive_util.py b/Lib/distutils/archive_util.py
index 61bc25e..4c5641b 100644
--- a/Lib/distutils/archive_util.py
+++ b/Lib/distutils/archive_util.py
@@ -100,7 +100,7 @@
                     z.write(path, path)
 
         if not dry_run:
-            z = zipfile.ZipFile(zip_filename, "wb",
+            z = zipfile.ZipFile(zip_filename, "w",
                                 compression=zipfile.ZIP_DEFLATED)
 
             os.path.walk(base_dir, visit, z)