diff --git a/sphinx/util/typing.py b/sphinx/util/typing.py
index 5cee1834a..db754bb03 100644
--- a/sphinx/util/typing.py
+++ b/sphinx/util/typing.py
@@ -77,7 +77,9 @@ def get_type_hints(obj: Any, globalns: Dict = None, localns: Dict = None) -> Dic
         # Failed to evaluate ForwardRef (maybe TYPE_CHECKING)
         return safe_getattr(obj, '__annotations__', {})
     except TypeError:
-        return {}
+        # Invalid object is given. But try to get __annotations__ as a fallback for
+        # the code using type union operator (PEP 604) in python 3.9 or below.
+        return safe_getattr(obj, '__annotations__', {})
     except KeyError:
         # a broken class found (refs: https://github.com/sphinx-doc/sphinx/issues/8084)
         return {}
diff --git a/tests/test_ext_autodoc.py b/tests/test_ext_autodoc.py
index b95441703..93b80f7ad 100644
--- a/tests/test_ext_autodoc.py
+++ b/tests/test_ext_autodoc.py
@@ -2237,7 +2237,7 @@ def test_name_mangling(app):
     ]
 
 
-@pytest.mark.skipif(sys.version_info < (3, 10), reason='python 3.10+ is required.')
+@pytest.mark.skipif(sys.version_info < (3, 7), reason='python 3.7+ is required.')
 @pytest.mark.sphinx('html', testroot='ext-autodoc')
 def test_type_union_operator(app):
     options = {'members': None}