diff --git a/.gitlab-ci.yml b/.gitlab-ci.yml
index d3890ec..ae12f0c 100644
--- a/.gitlab-ci.yml
+++ b/.gitlab-ci.yml
@@ -48,7 +48,7 @@ build:
 derive:
   stage: derive
   script:
-  - docker build --build_arg DEVUAN_VERSION="$DEVUAN_VERSION"
+  - docker build --build-arg DEVUAN_VERSION="$DEVUAN_VERSION"
            --tag "$CI_REGISTRY_NAME"/buildd:"$DEVUAN_VERSION"
            --file buildd.df
   - docker push "$CI_REGISTRY_IMAGE"/buildd:"$DEVUAN_VERSION"