The present disclosure relates to a high-frequency thermal therapy device, and includes an electrode for cauterizing a target lesion, a radio frequency generator for generating a radio frequency current, and a switch for opening and closing an electric circuit extending from the radio frequency generator to the electrode. A cauterization length of the electrode may be changed according to an operation of the switch. As a result, it is possible to prevent a normal area around the target lesion from being damaged, facilitate the treatment, and reduce cost for cauterization an equipment.