diff --git a/vars/tamarin.groovy b/vars/tamarin.groovy
index cb29495..308c876 100644
--- a/vars/tamarin.groovy
+++ b/vars/tamarin.groovy
@@ -85,7 +85,7 @@ def buildDockerImage() {
         def runTamarinScript = libraryResource 'com/cadoles/tamarin/run-tamarin.sh'
         writeFile file:'run-tamarin.sh', text:runTamarinScript
         
-        def safeJobName = URLDecoder.decode(env.JOB_NAME).toLowerCase().replace('/', '-')
+        def safeJobName = URLDecoder.decode(env.JOB_NAME).toLowerCase().replace('/', '-').replace(' ', '-')
         def imageTag = "${safeJobName}-${env.BUILD_ID}"
         return docker.build("tamarin:${imageTag}", ".")
     }