A 50-year-old man presented with pituitary apoplexy resulting in internal carotid artery occlusion manifesting as sudden onset of severe headache, right ptosis, and left hemiparesis, associated with visual impairment. Computed tomography showed a nodular mass, located in the sellar and suprasellar regions with early signs of acute cerebral ischemia. Magnetic resonance (MR) imaging indicated that the mass compressed the bilateral cavernous sinuses, resulting in obliteration of the cavernous portion of the right internal carotid artery. Right middle cerebral artery territory infarction was also found. Conservative therapy with steroids was given in the acute stage and repeated MR imaging showed recanalization of the internal carotid artery with reduction of the tumor size. The tumor was removed through the transsphenoidal approach to obtain a definitive diagnosis in the chronic stage. The histological diagnosis was consistent with non-functioning pituitary adenoma. Eye movement of this patient showed full recovery after the operation. Pituitary apoplexy resulting in internal carotid artery occlusion is rare. Surgical decompression through the transsphenoidal approach is appropriate, but the optimal timing should consider severe disturbance of visual acuity and visual field in the acute stage.