diff --git a/libarchive/__init__.py b/libarchive/__init__.py
index ec8c2d8..ed8010f 100644
--- a/libarchive/__init__.py
+++ b/libarchive/__init__.py
@@ -160,7 +160,7 @@ def is_archive(f, formats=(None, ), filters=(None, )):
     format(s)/filter(s).'''
     need_close : bool = False
     if isinstance(f, str):
-        f = open(f, 'r')
+        f = open(f, 'rb')
         need_close = True
     a = _libarchive.archive_read_new()
     for format in formats: