A 42-year-old male presented with a rare case of delayed aneurysmal formation of the intracranial ophthalmic artery after closed head injury manifesting as subarachnoid hemorrhage. Initial magnetic resonance angiography revealed no aneurysmal formation, but angiography 7 days after the injury demonstrated an intracranial ophthalmic artery aneurysm. Follow-up computed tomography angiography demonstrated enlargement of the aneurysm. The aneurysm was successfully treated by surgical resection. Histological examination revealed that the aneurysm was a pseudoaneurysm. Traumatic intracranial aneurysm (TICA) is rare and usually occurs in the peripheral arteries of the cerebral circulation or the basal portion of the internal carotid artery. The present case shows that failure to demonstrate an aneurysm on the initial angiography in the acute stage does not exclude the presence of traumatic aneurysm. This case clearly shows the time course of development of a TICA of the ophthalmic artery after closed head injury.