A traumatic giant aneurysm in the cavernous portion of the internal carotid artery is extremely rare vascular disorder. This aneurysm occurs in association with skull fracture and is frequently accompanied with fatal epistaxis. A 18 year old male suffered from massive epistaxis and he had the pulsating intranasal mass in the olfactory fissure. CT scan of the paranasal sinuses and carotid angiography showed traumatic giant aneurysm in the cavernous portion of the right internal carotid artery. With pterional approach, direct clipping of aneurysmal neck under the surgical microscope was performed, and his headache and epistaxis were relieved.