An electrode needle includes an electrode needle body, a metal tube, and an outer insulating tube. The electrode needle body is connected to a positive electrode of an RF generator. The metal tube is fixed around the electrode needle body and insulated from the electrode needle body. The metal tube is connected to a negative electrode of the RF generator. The outer insulating tube surrounds an upper part of the metal tube to expose a lower part of the metal tube. The outer insulating tube is movable longitudinally along the electrode needle body to vary an exposed area of the metal tube. At least one of a position, an area, and a cauterization speed of a site to be cauterized is controlled by varying the exposed area of the metal tube.