The medical treatment apparatus 1 includes a vibrating section 8 having first and second ultrasonic transducers 81 and 82, ultrasonic vibrations which linearly extend and the first and second ultrasonic transducers 81 and 82 generate A probe 6 for transmitting the biological tissue from one end to the other end, a jaw 9 enabling to hold the living tissue between the other end of the probe 6 and rotatable about the central axis of the probe 6, a jaw 9 , An output calculating section for calculating respective outputs for driving the first and second ultrasonic transducers 81 and 82, respectively, based on the rotation angle of the jaw 9, a first calculating section , A vibration driving unit which is electrically connected to the second ultrasonic transducers 81 and 82 and drives the first and second ultrasonic transducers 81 and 82 with the respective outputs calculated by the output calculating unit, . The respective outputs are arranged such that the vibration direction of the other end of the probe 6 due to the ultrasonic vibration of the first and second ultrasonic transducers 81 and 82 as viewed from the direction along the central axis is changed in the direction from the central axis toward the jaw 9 .医療用処置装置1は、第1,第2超音波振動子81,82を有する振動部8と、直線状に延び、第1,第2超音波振動子81,82がそれぞれ発生した超音波振動を一端から他端に伝達するプローブ6と、プローブ6の他端との間で生体組織を挟持可能とするとともに、プローブ6の中心軸を中心として回転可能とする顎部9と、顎部9の回転角を検出する回転角検出部と、顎部9の回転角に基づいて、第1,第2超音波振動子81,82をそれぞれ駆動する各出力を算出する出力算出部と、第1,第2超音波振動子81,82に電気的にそれぞれ接続し、出力算出部にて算出された各出力で第1,第2超音波振動子81,82をそれぞれ駆動する振動駆動部と、を備える。上記各出力は、上記中心軸に沿う方向から見て第1,第2超音波振動子81,82の超音波振動によるプローブ6の他端の振動方向を上記中心軸から顎部9に向かう方向に設定する出力である。
