diff --git a/action.yml b/action.yml
index 9d9ad77..e4511aa 100644
--- a/action.yml
+++ b/action.yml
@@ -13,9 +13,11 @@ inputs:
     required: true
   name:
     description: "SSH key file name (default: id_rsa)"
+    required: false
     default: "id_rsa"
   known-hosts:
     description: "public keys of SSH servers"
+    required: false
     default: ""
 runs:
   using: "node12"