The first reported the neural blockade of ganglion impar for pain control of perineal pain in 1990 by Plancarte and his fellows. they used 6ml of 10 percent phenol. but the point of issues, same as other neurolytics, are that it is impossible to check and control its spreading, so it might be possible to destruct the coccygeal plexus and sacral nerve, and also it has only short action time. Because of these problems, it could be very dangerous to attempt this procedure especially not for relieving the pain on cancer terminal patient, but for the sympathectomy of ganglion impar on the other purpose. We used the RF generator which had the control ability to point out the destructive lesion accurately. inserted We made the small burr hole on the sacrum near the sacrococcygeal junction directly, through the hole, and performed thermocoagulation to the ganglion impar.