diff --git a/scripts/clean_rosdep_yaml.py b/scripts/clean_rosdep_yaml.py
index 245f48026c099..1fccfebe274ed 100755
--- a/scripts/clean_rosdep_yaml.py
+++ b/scripts/clean_rosdep_yaml.py
@@ -64,5 +64,5 @@ def prn(n, nm, lvl):
     for a in sorted(iny):
         buf += prn(iny[a], a, 0)
 
-    with io.open(args.outfile, 'w', encoding='utf-8') as f:
-        f.write(buf)
+    with io.open(args.outfile, 'wb') as f:
+        f.write(buf.encode('utf-8'))