Aortic pseudoaneurysm is a rare, life-threatening complication after cardiac or aortic surgery. In this article, we report reoperation on an 86-year-old man undergoing total arch replacement and omentoplasty for an infectious aortic aneurysm, 5 years previously. He was transferred to our hospital and fell into shock. Prompt drainage of the right-side pleural cavity manifested 2000 ml of blood. Computed tomography revealed contrast extravasation into a pseudoaneurysm, which arose from the proximal anastomotic site of the ascending aorta. The patient underwent emergent surgery that included an extremely careful dissection of the omentum and pericardial adherences, through the re-sternotomy. The patient recovered without neurological sequelae.