diff --git a/src/model/docker.ts b/src/model/docker.ts
index 8df85138..d0f8915f 100644
--- a/src/model/docker.ts
+++ b/src/model/docker.ts
@@ -85,7 +85,7 @@ class Docker {
         --volume "${runnerTempPath}/_github_home":"/root" \
         --volume "${runnerTempPath}/_github_workflow":"/github/workflow" \
         --volume "${workspace}":"/github/workspace" \
-        ${sshAgent ? '--volume ' + sshAgent + ':/ssh-agent' : ''} \
+        ${sshAgent ? `--volume ${sshAgent}:/ssh-agent` : ''} \
         ${sshAgent ? '--volume /home/runner/.ssh/known_hosts:/root/.ssh/known_hosts:ro' : ''} \
         ${image}`;