A 76-year-old man presenting with symptomatic right carotid artery stenosis underwent carotid artery stenting (CAS). Based on ultrasonography images showing a progressing stenosis in the right carotid artery, percutaneous transluminal angioplasty (PTA) was repeatedly performed three times for 1.5 years. During follow-up, peak systolic velocity increased and revised CAS was performed with 4th PTA. One hour post 2nd CAS, restlessness and partial seizure were noted. Head CT did not reveal any cerebral hemorrhage, and the value of regional saturation of oxygen of right side was higher than that of left side, leading to a diagnosis of hyperperfusion syndrome. Under general anesthesia, the patient was administered antiepileptic drugs and the blood pressure was strictly controlled. After recovering from acute respiratory distress syndrome, the patient underwent extubation on day 14 and initiated rehabilitation. On day 88 post 2nd CAS, the patient was discharged with no significant disability (mRS 1).