diff --git a/README.md b/README.md
index 9a52ecd4..8099b96a 100644
--- a/README.md
+++ b/README.md
@@ -30,6 +30,8 @@ Some features:
     to: obiwan@example.com,yoda@example.com
     # Required sender full name (address can be skipped):
     from: Luke Skywalker # <user@example.com>
+    # Optional whether this connection use TLS (default is true if server_port is 465)
+    secure: true
     # Optional plain body:
     body: Build job of ${{github.repository}} completed successfully!
     # Optional HTML body read from file:
diff --git a/action.yml b/action.yml
index b1e24dae..bd87873b 100644
--- a/action.yml
+++ b/action.yml
@@ -26,6 +26,9 @@ inputs:
   from:
     description: Full name of mail sender (might be with an email address specified in <>)
     required: true
+  secure:
+    description: Whether this connection use TLS (default is true if server_port is 465)
+    required: false
   body:
     description: Body of mail message (might be a filename prefixed with file:// to read from)
     required: false
diff --git a/main.js b/main.js
index 01297c95..d2cf4a5a 100644
--- a/main.js
+++ b/main.js
@@ -38,6 +38,7 @@ async function main() {
         const subject = core.getInput("subject", { required: true })
         const from = core.getInput("from", { required: true })
         const to = core.getInput("to", { required: true })
+        const secure = core.getInput("secure", { required: false })
         const body = core.getInput("body", { required: false })
         const htmlBody = core.getInput("html_body", { required: false })
         const cc = core.getInput("cc", { required: false })
@@ -50,7 +51,7 @@ async function main() {
         const transport = nodemailer.createTransport({
             host: serverAddress,
             port: serverPort,
-            secure: serverPort == "465",
+            secure: secure ? true : serverPort == "465",
             auth: {
                 user: username,
                 pass: password,