A medical treatment tool includes: an insert portion at least a part of which is provided by a flexing portion that is adapted to be flexed, the insert portion being adapted to be inserted into a human body of a patient and an inflatable body provided on an outer circumference of the flexing portion, the inflatable body being inflated in a radial direction of the flexing portion. An axial distal end portion of the inflatable body is fixed to the insert portion while a proximal end portion of the inflatable body is axially movable relative to the insert portion.
