The ultrasonic treatment instrument 11 includes a vibration generating unit 16 having a first screw portion 24 and generating ultrasonic vibration, a probe 16 which extends along the longitudinal axis C and transmits ultrasonic vibration generated in the vibration generating portion 16 A second threaded portion 31 provided on the probe body 27 so as to face the first threaded portion 24 and having a spiral in a direction opposite to that of the first threaded portion 24 and a second threaded portion 31 provided on the distal end of the probe main body 27 , And a probe (14). The ultrasonic treatment instrument 11 includes a coupling portion 17 having a first engagement portion 32 engaging with the first screw portion 24 and a second engagement portion 33 engaging with the second screw portion 31. The connecting portion 17 rotates the vibration generating portion 16 and the probe 14 so that the ultrasonic vibration can be transmitted to the probe 14 side by rotating the connecting portion 17 in the first direction around the longitudinal axis C with respect to the vibration generating portion 16 and the treatment portion 28 And is rotated in a second direction opposite to the first direction to separate the vibration generating unit 16 from the probe 14.超音波処置具11は、第1ねじ部24を有するとともに超音波振動を発生する振動発生部16と、長手軸Cに沿って延びるとともに振動発生部16で発生した超音波振動が伝達されるプローブ本体27と、プローブ本体27に第1ねじ部24と対向するように設けられ第1ねじ部24とは逆向きのらせんを有する第2ねじ部31と、プローブ本体27の先端部に設けられる処置部28と、を有するプローブ14と、を備える。超音波処置具11は、第1ねじ部24と係合する第1係合部32と、第2ねじ部31と係合する第2係合部33と、を有する連結部17を備える。連結部17は、振動発生部16および処置部28に対して長手軸C周りの第1方向に回転させることでプローブ14側に前記超音波振動を伝達可能に振動発生部16とプローブ14とを連結し、第1方向と逆向きの第2方向に回転させることで振動発生部16とプローブ14とを分離させる。
