An 80-year-old man with inappetence and dyspnea was taken to our hospital by ambulance. His abdomen was distended and hard. A bladder diverticulum perforation was suspected based on an abdominal computed tomography (CT) examination. We consulted a urologist, who placed an indwelling bladder catheter and washed the bladder, however the patient showed signs of septic shock. A subsequent CT scan performed 110 minutes after the previous scan showed portal venous gas, intraperitoneal free gas, and bilateral femoral vein gas. Emergency abdominal surgery revealed a perforation of the bladder diverticulum and acute pan-peritonitis. We performed perforation closure and drainage, with intensive care after the operation, however the patient died from multiple organ failure 40 hours after the operation. In this case, gas in the portal vein, abdominal cavity, and femoral vein appeared in a short time. The case of portal venous gas accompanied by systemic venous gas is rare and valuable, since it suggests that the gas in the portal vein enter the systemic vein through a portosystemic shunt.