PROBLEM TO BE SOLVED: To provide a treatment instrument 20 which receives an AC magnetic field wirelessly and in which temperature increase is hard to occur.SOLUTION: A treatment instrument 20 includes: a grip part 24； an ultrasonic vibrator 23； a horn 22 whose base end part is mechanically coupled with the ultrasonic vibrator 23 and which consists of rod-like metal； a treatment part 21 which is inserted into a body of a subject 9 via an insertion hole 19H of a trocar 10 having a power transmission coil 19 generating an AC magnetic field and which is mechanically coupled with the tip of the horn 22； and a solenoid-shaped power receiving coil 29 which wirelessly receives power with inductive coupling with the power transmission coil 19 and arranged closer to the grip part side than the ultrasonic vibrator 23.【課題】 交流磁界をワイヤレスで受電する、温度が上昇しにくい処置具２０を提供する。【解決手段】 処置具２０は、把持部２４と、超音波振動子２３と、超音波振動子２３と基端部が機械的に結合している棒状の金属からなるホーン２２と、交流磁界を発生する送電コイル１９を有するトロッカー１０の挿入孔１９Ｈを介して被検体９の体内に挿入される、ホーン２２の先端部と機械的に結合している処置部２１と、送電コイル１９と誘導結合して電力を無線受電する、超音波振動子２３よりも把持部側に配設されているソレノイド形状の受電コイル２９と、を具備する。【選択図】図２
