We report on a case of thymic cyst which was successfully treated with mediastinoscopic resection combined with a sternum lift technique. A 62-year-old man was admitted to our hospital with a thymic cyst, which was causing chest discomfort and was increasing in size. The tumor was located above the pulmonary artery in the anterior mediastinum. He underwent mediastinoscopic resection while lifting the inferior portion of the sternum with a Laparolift. The cyst was resected sharply and bluntly with the Harmonic Scalpel without rupture. The patient was discharged on the 6th postoperative day in a good condition. Mediastinoscopic resection of a thymic cyst through a xiphoid approach is a useful surgical approach because of the absence of postoperative pain and because it allows early discharge from the hospital.