The patient was a 67-year-old man. He was admitted to a local hospital with severe back pain, and left hydrothorax was noted by a chest X-ray. Then, he went into shock and was transferred to our hospital. Enhanced computed tomography (CT) showed massive liquid retention of the left thorax, but no aortic dissection or aneurysms. He was diagnosed with spontaneous aortic rupture, and endovascular treatment was chosen because of his unstable hemodynamics. He fell into cardiac arrest 10 minutes after the operation started, and we implanted 2 stent-grafts while giving cardiac massage. After 23 minutes cardiac massage, he was resuscitated. He was discharged without any complication. Even if no signs of aortic aneurysms or aortic dissection were detected, the possibility of spontaneous aortic rupture should be suspected. Endovascular treatment is a reliable option in the case of unstable hemodynamics.