A 52-year-old man with a history of von Recklinghausen's disease presented to our hospital with abrupt onset of right chest and back pain. A contrast-enhanced chest computed tomography (CT) revealed massive right hemothorax, extravasation of the contrast medium at a branch of the right subclavian artery, and a tumor surrounding the second right dorsal rib. Based on findings from emergent angiography, hemothorax secondary to the rupture of an aneurysm of a branch of the right subclavian artery was diagnosed, and transcatheter arterial embolization(TAE) was performed. After hemostasis, intrathoracic hematoma was removed by surgery, and a recurrence of hemothorax did not occur until at least 8 months after the initial TAE procedure.