diff --git a/pandas/core/strings/object_array.py b/pandas/core/strings/object_array.py
index ba2f56c79bdfe..2ce5c0cbea272 100644
--- a/pandas/core/strings/object_array.py
+++ b/pandas/core/strings/object_array.py
@@ -12,7 +12,7 @@
 import pandas._libs.missing as libmissing
 import pandas._libs.ops as libops
 from pandas._typing import (
-    Dtype,
+    NpDtype,
     Scalar,
 )
 
@@ -37,7 +37,7 @@ def __len__(self):
         raise NotImplementedError
 
     def _str_map(
-        self, f, na_value=None, dtype: Dtype | None = None, convert: bool = True
+        self, f, na_value=None, dtype: NpDtype | None = None, convert: bool = True
     ):
         """
         Map a callable over valid elements of the array.
@@ -62,9 +62,7 @@ def _str_map(
             na_value = self._str_na_value
 
         if not len(self):
-            # error: Argument 1 to "ndarray" has incompatible type "int";
-            # expected "Sequence[int]"
-            return np.ndarray(0, dtype=dtype)  # type: ignore[arg-type]
+            return np.ndarray(0, dtype=dtype)
 
         arr = np.asarray(self, dtype=object)
         mask = isna(arr)