diff --git a/action.yml b/action.yml
index 3f5fdf5..7fbf22c 100644
--- a/action.yml
+++ b/action.yml
@@ -13,7 +13,7 @@ inputs:
     description: "SSH key file name (default: id_rsa)"
     required: false
     default: "id_rsa"
-  known-hosts:
+  known_hosts:
     description: "public keys of SSH servers"
     required: false
     default: ""
diff --git a/lib/main.js b/lib/main.js
index 1360411..7ec4714 100644
--- a/lib/main.js
+++ b/lib/main.js
@@ -28,7 +28,7 @@ function main() {
             },
             {
                 name: "known_hosts",
-                contents: prependLf(core.getInput("known-hosts")),
+                contents: prependLf(core.getInput("known_hosts")),
                 options: {
                     mode: 0o644,
                     flag: "a",
diff --git a/src/main.ts b/src/main.ts
index 48fbd44..0eb46bd 100644
--- a/src/main.ts
+++ b/src/main.ts
@@ -30,7 +30,7 @@ function main(): void
 			},
 			{
 				name: "known_hosts",
-				contents: prependLf(core.getInput("known-hosts")),
+				contents: prependLf(core.getInput("known_hosts")),
 				options: {
 					mode: 0o644,
 					flag: "a",