We have encountered a case of superior mediastinal neurinoma which grows through the intercostal space and advances into the erector spinal muscles. Neurinoma which shows such a growth pattern is rare. MRI is useful in making preoperative evaluation. For operation, non-open chest extrapleural extirpation was successfully performed by the supraclavicular and posterior approach. This type of operation has the following advantages: surgical stress is less; postsurgical pain is mild, etc.