Treatment system 10 includes a high frequency power source 73, a heating power source 83, based on a pair of conductors 52a, 52b and a pair of jaws 36a having a heater member 53, and 36b, a heating power source 83 to the temperature of the heater member 53 as well as constant temperature control, when the heating power that decreases after the maximum value is increased after start of the application of the thermal energy becomes the threshold power below, or when the decreasing rate of the heating power is equal to or less than the threshold speed, It comprises a control unit 94 which controls to terminate the application of the thermal energy of the,.処置システム10は、高周波電源73と、発熱用電源83と、一対の導電体52a、52bとヒーター部材53とを有する一対のジョー36a、36bと、発熱用電源83をヒーター部材53の温度に基づき定温制御すると共に、熱エネルギの印加開始後に増加し最大値を示した後に減少する発熱用電力が閾値電力以下になった場合、または前記発熱用電力の減少速度が閾値速度以下になった場合、前記熱エネルギの印加を終了するように制御する制御部94と、を具備する。
