diff --git a/README.md b/README.md
index cf28cfe..95e1ac6 100644
--- a/README.md
+++ b/README.md
@@ -140,7 +140,7 @@ It's recommended to use [Docker](https://www.docker.com/) to build ffmpeg.js.
 
 3.  Build everything:
     ```bash
-    docker run --rm -it -v /path/to/ffmpeg.js:/mnt -w /opt kagamihi/ffmpeg.js
+    docker run --rm -it -v /absolute/path/to/ffmpeg.js:/mnt -w /opt kagamihi/ffmpeg.js
     # cp -a /mnt/{.git,build,Makefile} . && source /root/emsdk/emsdk_env.sh && make && cp ffmpeg*.js /mnt
     ```