A 61-year-old man with the descending thoracic aneurysm associated with the infra-renal abdominal aneurysm was operated at the same time using the temporary bypass from right subclavian artery to right femoral artery safely. In order to observe the spinal cord function, SEP and ESP were recorded. Anastomosis of the prosthetic graft to the temporary bypass was prepared beforehand to preserve the spinal cord function during aortic cross clamping, if needed. If both aneurysms are present in the thoracic and abdominal cavity, special considerations are required, at one or two-staged operation and what adjuncts will be used to perform the repairs safely. In this case, the repair of thoracic lesion underwent well, and the repair of the abdominal one followed it. His postoperative course was uneventful.