Disclosed is a handpiece for a high frequency thermotherapy device with an improved cooling function, in which a cooling means for cooling an electrode unit installed inside the handpiece is arranged so to prevent the electrode unit from overheating and to easily adjust the temperature of the electrode unit, thereby efficiently controlling the amount of required energy according to characteristics of a human body and tumor locations which vary from patient to patient. The disclosed handpiece for a high frequency thermotherapy device with an improved cooling function is installed in the high frequency thermotherapy device so as to apply high frequency current to an affected part, and the handpiece comprises: a handpiece body having a disk shape and a bottom surface with an installation groove a handpiece handle coupled to the center of an upper surface of the handpiece body a bolus which is coupled beneath the handpiece body and of which the inside is filled with cooling water supplied through the handpiece body an electrode unit which is coupled to a lower surface of the handpiece body and installed inside the bolus so as to be interposed between the bolus and a lower electrode unit arranged beneath the affected part and applies high frequency current generated from a high frequency generating unit to the affected part and a thermoelectric element attached to an upper surface of the electrode unit so as to be accommodated in the installation groove of the handpiece body.
