diff --git a/changelog/7123.bugfix.rst b/changelog/7123.bugfix.rst
new file mode 100644
index 0000000000..d416a902e3
--- /dev/null
+++ b/changelog/7123.bugfix.rst
@@ -0,0 +1,3 @@
+:user:`gaoflow` fixed :meth:`iris.cube.Cube.rolling_window` so that it no
+longer raises a ``TypeError`` when the cube has a lazy auxiliary coordinate
+along the windowed dimension. (:issue:`6480`)
diff --git a/lib/iris/cube.py b/lib/iris/cube.py
index 44be3a63d7..4ddba3781f 100644
--- a/lib/iris/cube.py
+++ b/lib/iris/cube.py
@@ -5243,12 +5243,12 @@ def rolling_window(
                 # window and the bounds are the first and last points in the
                 # window as with numeric coordinates.
                 new_points = np.apply_along_axis(lambda x: "|".join(x), -1, new_bounds)
-                new_bounds = new_bounds[:, (0, -1)]
+                new_bounds = new_bounds[:, [0, -1]]
             else:
                 # Take the first and last element of the rolled window (i.e.
                 # the bounds) and the new points are the midpoints of these
                 # bounds.
-                new_bounds = new_bounds[:, (0, -1)]
+                new_bounds = new_bounds[:, [0, -1]]
                 new_points = np.mean(new_bounds, axis=-1)
 
             # wipe the coords points and set the bounds
diff --git a/lib/iris/tests/unit/cube/test_Cube.py b/lib/iris/tests/unit/cube/test_Cube.py
index d91c7e81c0..103aedd558 100644
--- a/lib/iris/tests/unit/cube/test_Cube.py
+++ b/lib/iris/tests/unit/cube/test_Cube.py
@@ -1086,6 +1086,20 @@ def test_lazy(self):
         )
         _shared_utils.assert_masked_array_equal(expected_result, res_cube.data)
 
+    def test_lazy_aux_coord(self):
+        window = 2
+        self.cube.add_aux_coord(AuxCoord(da.arange(6), long_name="lazy_extra"), 0)
+        res_cube = self.cube.rolling_window("val", iris.analysis.MEAN, window, mdtol=0)
+        result_coord = res_cube.coord("lazy_extra")
+        assert result_coord.has_lazy_points()
+        assert result_coord.has_lazy_bounds()
+        expected = AuxCoord(
+            np.array([0.5, 1.5, 2.5, 3.5, 4.5]),
+            bounds=np.array([[0, 1], [1, 2], [2, 3], [3, 4], [4, 5]]),
+            long_name="lazy_extra",
+        )
+        assert result_coord == expected
+
     def test_ancillary_variables_and_cell_measures_kept(self, dataless):
         if dataless:
             self.cube.data = None