A 55-year-old female presented with subarachnoid hemorrhage and was admitted to the department of neurosurgery. Because she had severe hypertension, systemic evaluation was performed. Computed tomography showed a right adrenal tumor which was suspected to be a pheochromocytoma because catecholamine levels were very high in both serum and 24-hour urine. She did not awaken from anesthesia after laparoscopic adrenalectomy and laboratory tests showed that her blood sugar concentration was 33 mg/dl. This hypoglycemia was controlled by continuous infusion of a 50% glucose solution at 40 ml/h and she became conscious the next morning. We gradually decreased the amount of glucose infused and stopped the infusion on postoperative day 4. The tumor was pathologically diagnosed as a pheochromocytoma.