diff --git a/flask_restx/reqparse.py b/flask_restx/reqparse.py
index de5b9bd5..8461f0ec 100644
--- a/flask_restx/reqparse.py
+++ b/flask_restx/reqparse.py
@@ -300,6 +300,8 @@ def __schema__(self):
             )
         if self.action == "append":
             param["items"] = {"type": param["type"]}
+            if "pattern" in param:
+                param["items"]["pattern"] = param.pop("pattern")
             param["type"] = "array"
             param["collectionFormat"] = "multi"
         if self.action == "split":