diff --git a/How-to-install.md b/How-to-install.md
index e2c499f0..c520eefd 100644
--- a/How-to-install.md
+++ b/How-to-install.md
@@ -63,7 +63,7 @@ Explanations :
 - `--cert-home` is a customized dir to save the certs you issue.  By default, it's saved in `--config-home`.
 - `--accountemail  ` is the email used to register an account to Let's Encrypt,  you will receive a renewal notice email here.
 - `--accountkey` is the file saving your account private key.  By default, it's saved in `--config-home`.
-- `--user-agent`  is the user-agent header value used to send to Let's Encrypt.
+- `--useragent`  is the user-agent header value used to send to Let's Encrypt.
 - `--nocron` install acme.sh without cronjob