To provide an ultrasonic treatment tool capable of improving ability for holding an organ tissue between a jaw having teeth and a blade and smoothly progressing treatment without catching the organ tissue between teeth in spite of that ability.

Concerning an ultrasonic treatment tool 1 having a blade 70 for ultrasonic vibrations and a jaw 50 facing this blade so as to treat the organ tissue held between the jaw 50 and the blade 70 with ultrasonic vibrations, teeth 67 are provided on the holding plane side of the jaw 50 facing the blade 70 and the tooth 67 at the turn supporting point side part of the jaw 50 is formed so as to easily separate the organ tissue after treatment in comparison with the form of the tooth 67 at the turn top end point side part of the jaw 50.