A grasping surface opposed to a second jaw is provided on an outer surface in a first jaw of the grasping treatment unit, and a heat applying portion applying heat to a treated target is provided in a grasping-surface-side part in the first jaw. The heat applying portion includes a projection portion in which the grasping surface projects toward the second jaw, and the projection portion includes a first thermal conduction portion, and a second thermal conduction portion with a thermal conductivity which is different from that of the first thermal conduction portion. The second thermal conduction portion is continuous with the first thermal conduction portion in a longitudinal direction of the first jaw.
