We report a valuable case in which a spontaneous intercostal arterial aneurysmal rupture associated with neurofibromatosis type 1, and a re-rupture after embolization of the aneurysm were successfully treated by endovascular embolization without surgery. Our case calls for attention as it indicates that recurrent aneurysmal rupture can occur even after an embolization or surgery. It is important to carefully observe the course of the patient by follow-up computed tomography (CT) or angiography in such cases.