Thoracic sympathetic nerve block has a wide range of therapeutic applications which clinicians utilize neurolytics or perform operative sympathectomy. All methods have advantages and disadvantages. We performed "thoracic sympathetic ganglion cauterization" using resectoscope as it is less invasive and more effective than traditional operative methods. Successful procedures were performed involving 2 cases of idiopathic hyperhidrosis and 1 case of sympathetically maintained pain on chest and upper extremity. We experienced failure with one case of idiopathic hyperhidrosis due to severe pleural adhesion. There was also a case of complication of periganglional hemorrhage and parenchymal lung perforation which we successfully treated.