In a grasping treatment unit in which a first jaw is openable and closable relative to a second jaw, a frame member is provided in the first jaw. The frame member includes a plate-shaped base portion forming a grasping surface side end face in the frame member, and a column extension extending from the base portion toward a back surface in the frame member and having one end continuous with the base portion. The column extension defines a space in which the frame member is a defining surface between the base portion and the back surface of the first jaw.
