The subject was a 75-year-old man who had been undergoing medical treatment for anamnesis of hypertension and hyperlipidemia since the age of 65. Three months previously, he had symptoms of atheroma thrombotic cerebral infarction and medical treatment of an antiplatelet agent was started. During his hospitalization for rehabilitation of the left hemiplegia after cerebral infarction, abdominal pain appeared. The blood biochemistry inspection showed high inflammatory reaction, but there was no anemia. Acute acalculous cholecystitis was diagnosed based on abdominal US and CT images. While waiting till the operation, the abdominal pain appeared again 9 days after the onset of acute cholecystitis. He was a shock state of the blood pressure 95/66 mmHg and the pulse rate 112/minute. The blood biochemistry inspection showed aggravation of inflammation, anemia, elevation of hepatobiliary enzyme, and jaundice. Gallbladder bleeding by ruptured pseudoaneurysm was diagnosed by abdominal enhanced CT, and laparotomic cholecystectomy was enforced. Although rupture of the pseudoaneurysm of the gallbladder after acalculous cholecystitis is rare, it must be carefully considered when the ischemia in an antiplatelet therapy with a vascular lesion is the cause of the cholecystitis, because gallbladder bleeding may be caused from formation of the pseudoaneurysm several days after the onset of symptoms.