The hemothorax due to rupture of arteriovenous fistula is very rare and only 6 cases of this complication have been reported in Japanese literature. 44-year-old male complained of chest pain and dyspnea. A chest roentgenogram revealed right pleural effusion and an abnormal pulmonary shadow. By further examination including pulmonary angiography, the rupture of pulmonary arteriovenous fistula into right pleural cavity was diagnosed. Partial resection of the right lung containing arteriovenous fistula was successfully performed and postoperative course was uneventful.