Left pneumonectomy and concomitant resection of the invaded aorta were performed by the simple temporary bypass method. The patient was a 59-year-old male with the chief complaint of left thoracic pain. The 57×43×35 mm tumor was in a region centering on segment 6 of the left lung and had infiltrated the descending aorta. It was diagnosed as T4NOMO, Stage IIIb. A bypass for blood flow was established between the aortic arch avobe the invasion and the left femoral artery, after ligation of the pulmonary artery and vein and closure of the left bronchial stump. Vascular blocking forceps were applied to the descending aorta above and below the tumor infiltration, and two thirds of the circumference of the invaded aortic wall, 4.0×3.0 cm, along with the tumor, was resected. Reconstruction was performed with an 18mm Cooly double velour graft. Blood pressure was monitored with a pressure probe inserted into the right femoral artery. It did not fall below 60 mmHg during the operation. Local recurrence was observed 10 montns post-operatively, and the patient is now receiving radiation therapy.