The cerebral vasospasm after clipping surgery of unruptured aneurysm is uncommon. A 44-year-old man with unruptured left middle cerebral artery(MCA) aneurysm had clipping surgery. From the third postoperative day, he presented with drowsy mentality, dysphasia and right hemiparesis. Computed tomographic scans showed low density area in frontotemporal lobe and midline shift. Transfemoral cerebral angiography revealed severe vasospasm in supraclinoid internal carotid artery, anterior cerebral artery, and MCA on the operative side. We performed left frontotemporoparietal craniectomy and hypertensive-hypervolemic therapy. He recovered without neurological deficits but for dysphasia. Neurosurgeon should be alert to the possibility of vasospasm after clipping surgery even in case of unruptured cerebral aneurysm.