diff --git a/action/main.py b/action/main.py
index ee7c17821..1a0569194 100644
--- a/action/main.py
+++ b/action/main.py
@@ -25,7 +25,7 @@
     if VERSION.startswith("@"):
         req[0] = f"git+https://github.com/akaihola/darker{VERSION}#egg={req[0]}"
     elif VERSION.startswith(("~", "=", "<", ">")):
-        req[1] += VERSION
+        req[0] += VERSION
     else:
         req[0] += f"=={VERSION}"
 linter_options = []