Uncommon case of superior vena caval obstruction secondary due to idiopathic fibrous mediastinitis was reported. A 38-year-old female was admitted in our hospital with the complaint of dyspnea and facial edema. Venography revealed occlusion of vena cava. Venous pressure showed 30 cmH2O in the external carotid vein. Mediastinal computed tomogram revealed no tumor but calcification in the anterior mediastinal fatty tissue. Therefore, with a 12 cm EPTFE, left brachiocephalic vein-right atrium bypass operation was performed. Facial edema was disappeared dramatically in early postoperative stage. She is uneventful 20 months after the operation.