We report a case of a simultaneous bilateral pneumothorax (buffalo chest). A 75-year-old man who had undergone resection of an esophageal carcinoma had difficulty in breathing and lost consciousness. He was transported to our hospital and diagnosed as a simultaneous bilateral pneumothorax. He underwent bilateral chest drainages, and was hospitalized. Because of the continued air leak, an operation was performed. First, thoracoscopic bullectomy was performed from the left side. Changing the position, the water poured in the left thoracic cavity to test for air leaks flowed out to the right drain in large quantities;thus, a communication between both sides of the thoracic cavity became clear, although we could not find a pleural defect between the thoracic cavities.