Four cases of chronic subdural hematoma associated with intracranial aneurysm were reported. In two cases aneurysms were found at the peripheral portion of middle cerebral artery under the hematoma, and in other two cases aneurysms were found incidentally. The causality was discussed about subdural hematoma and intracranial aneurysm especially false aneurysm found in the peripheral artery under the hematoma. Radical operation of intracerebral aneurysm associated with chronic subdural hematoma should be performed after angiography and CT scan regardless the rupture of the aneurysm.