Multiple cerebral infarction developed in a 36-year-old woman with adenocarcinoma of the right lung with direct cardiac invasion. Neurological examination and brain MRI showed findings of ordinary infarction. Transesophageal echocardiography showed left atrial pedunculated mass which was the potential source of embolism. We report a rare case who had such multiple spontaneous tumor emboli large enough to result in clinically detectable cerebral infarction.