A 69-year-old man was admitted to our hospital because of massive hemoptysis. Bronchial arteriography showed no abnormal findings. Bronchoscopic findings revealed a small, reddish elevated lesion on the posterior surface of the left upper lobe bronchus. Since the patient developed massive hemoptysis four times in a month, he underwent ligation and transection of the left bronchial artery, and bronchoplasty. Histopathologically, the resected tissue showed a bronchial arterial aneurysm without any inflammatory changes. We concluded that the aneurysm had developed in a malformed vessel.