The patient was 62-year-old woman was brought to the emergency room with chest pain and dyspnea. Computed tomography revealed a hematoma around the ascending aorta, a notch in the aortic wall, pericardial effusion and a hematoma around the pulmonary artery. We diagnosed early thrombotic type of acute aortic dissection. An ascending aorta replacement was performed via median sternotomy under hypothermic circulatory arrest. Upon operation, there was a 1.0 cm intimal tear just above the left main trunk and there was no specific evidence of aortic dissection. So we diagnosed spontaneous aortic rapture. Her postoperative course was uneventful and she was discharged 18 days after surgery.