The disclosed technology is directed to a treatment tool comprises a shaft to extend from a proximal-end side toward a distal-end side. A first jaw is disposed on the distal-end portion of the shaft. A second jaw having a gripping surface that faces the first jaw, an opposed back surface of the gripping surface and a first engaging portion. The second jaw is angularly movable about a turn axis of the first engaging portion so as to be opened or closed with respect to the first jaw. A movable shaft having a recess defined in a distal-end and is movable along the longitudinal axis with respect to the shaft for angularly moving the second jaw about the turn axis with respect to the first jaw. A cover having a protrusion that protrudes toward a proximal-end side of the second jaw and a second engaging portion formed on the protrusion.
