PROBLEM TO BE SOLVED: To provide an adapter for medical treatment which can be attached/detached to/from an existing diagnostic ultrasonic probe, and can be used with a balloon.SOLUTION: An adapter 10 for medical treatment which is mounted to a tip part of a diagnostic ultrasonic probe formed with in a circumferential direction a balloon groove to which a marginal part of the opening of a balloon is fitted, includes an ultrasonic vibrator 2 for medical treatment radiating an ultrasonic wave for medical treatment, a substantially-semicylindrical housing 1 holding the ultrasonic vibrator 2 for medical treatment and mounted to the outer surface of the tip part of the ultrasonic probe, and a seal part 1b sealing a space between the inner surface of the housing 1 and the inner surface of the balloon groove.COPYRIGHT: (C)2015,JPO&INPIT【課題】既存の診断用の超音波プローブに着脱可能としつつ、バルーンとの併用を可能とする。【解決手段】バルーンの開口の縁部が嵌められるバルーン溝が周方向に形成された診断用の超音波プローブの先端部分に装着される治療用アダプタ10であって、治療用超音波を放射する治療用超音波振動子2と、該治療用超音波振動子2を保持し、超音波プローブの先端部分の外面に装着される略半円筒形のハウジング1と、該ハウジング1の内面とバルーン溝の内面との間の空間を塞ぐシール部1bとを備える治療用アダプタ10を提供する。【選択図】図2