We present a case of complete anterior papillary muscle rupture (PMR) due to localized papillary muscle infarction, without significant coronary artery disease. A 69-year-old woman was transferred to our hospital because of acute orthopnea and cardiogenic shock. Echocardiography showed severe mitral regurgitation due to anterior PMR, and emergency coronary angiography revealed no obstructive disease in the coronary arteries. Emergency mitral valve replacement was performed with intra-aortic balloon pumping support. Intraoperatively, the anterolateral papillary muscle was found to be completely ruptured. With maximal posterior leaflet preservation, mitral valve replacement was successfully performed. Her postoperative course was uneventful. Pathologic examination showed both old fibrosis and new ischemic lesion in the same resected papillary muscle. It could be speculated that repeated localized subendocardial infarction caused so-called spontaneous PMR.