We report a case of a 69-year-old man in whom double aortic aneurysms of the arch and descending aorta with a right aortic arch and mirror-image branching were diagnosed by three-dimensional computed tomography and aortography. These techniques are useful to assess the exact anatomy of the lesion and branches of the arch. The patient was successfully treated by a two-stage operation consisting of aortic arch replacement followed by descending aorta replacement.