We report herein an uncommon clinical case of pulmonary artery aneurysm in Behçet's syndrome, for which only a few reports have been published in the literature to date. A 68-year-old Japanese male, who was referred for recurrent fever of unknown origin, anemia and pulmonary nodular opacities, was treated by right lower lobectomy followed by postoperative oral administration of colchicine and corticosteroid. Postoperative pathological examination confirmed a diagnosis of pulmonary artery aneurysm accompanied by vasculitis and thrombi. Clinical and radiographic feature are presented herein.