This medical treatment tool includes: an end effector which has a first forceps piece and a second forceps piece an operating member that the pair of forceps pieces to rotate and opens/closes and a link member whose distal end portion is coupled to the forceps piece, and whose proximal end portion is coupled to the operating member wherein the drive axis of the proximal end portion is parallel with the axis of the operating member the distance between the distal end portion and the drive axis of the proximal end portion is shorter than the length of the link member and the length of projection on the drive axis is shorter than the length of projection on the drive axis of a line segment which connects the distal end portion and the center of rotation.
