A medical treatment tool includes: a long flexible section a movable member that is attached to a distal end of a flexible section so as to be relatively movable in a longitudinal-axis direction of the flexible section a grasper that is attached to the movable member and that includes a pair of jaws that can be opened and closed, at least one of which is supported so as to be pivotable about a shaft intersecting the longitudinal axis and a tension transmission disposed in the flexible section so as to be able to advance and retract in the longitudinal-axis direction, having one end joined to the jaws, and pivoting the jaws by transmitting the tension.
