diff --git a/Dockerfile b/Dockerfile
index 17743de..f102832 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -7,7 +7,7 @@ LABEL AlternativeImageName="wollud1969/build-env-c"
 
 RUN \
   apt-get update && \
-  apt-get install -y gcc g++ libcunit1 && \
+  apt-get install -y gcc g++ libcunit1 libcunit1-dev && \
   rm -rf /var/lib/apt/lists/*