Abstract: The bending brake comprises an intermediate member (10) fixed to the upper toolplate of the brake, and at least one jaw (20) connected to the intermediate member (10) and rotatable about a horizontal axis (R) parallel to the longitudinal axis of the intermediate member (10); the lower portions (20′) of the jaw (20) and of the intermediate member (10) are arranged to clamp and alternately release the tool shank (8). There are provided pressing members (30), carried by the intermediate member (10) and connected thereto in such a manner as to be able to slide in a transverse direction, to thrustingly act on the upper portion (20″) of the jaw to cause it to rotate, and a thrust member (40) having its longitudinal axis (B) parallel to the longitudinal axis of the intermediate member (10).