diff --git a/tox.ini b/tox.ini
index 2abdad6..bafb326 100644
--- a/tox.ini
+++ b/tox.ini
@@ -57,6 +57,7 @@ deps = mypy
        types-appdirs
        types-Pillow
        types-pyserial
+       types-pywin32>=306.0.0.6
        hypothesis>=6.83
        jaconv
 commands = mypy src test