A 28-year-old right-handed woman had been diagnosed with a tumor of 30 mm in a diameter at the right first intercostal space adjacent to brachial nerve plexus. It was incidentally detected by medical checkup examination five years ago. Because the tumor enlarged to 36 mm in five years without any symptoms, thoracoscopic tumor resection was planned for diagnosis. Intraoperative neurophysiological monitoring (IONM) was performed to prevent brachial plexus nerve injury. The tumor was totally removed via thoracoscopic approach without postoperative neurological deficit. Histopathological diagnosis was schwannoma. In order to reduce the risk of neural injury, IONM is useful in thoracoscopic removal of the peripheral nerve tumor.