A grasping treatment unit configured to grasp and treat a living tissue, the grasping treatment unit comprising: a first jaw which extends from a proximal portion toward a distal portion, and which has an outer surface exposed to an outside; a second jaw which extends from a proximal portion toward a distal portion, and which is openable and closable relative to the first jaw ; a treatment surface which is provided on the outer surface of the first jaw , and which faces the second jaw , the treatment surface being configured to treat the living tissue; and a heating portion including a heating wire , the heating wire being disposed in a range from the proximal portion to the distal portion in the first jaw , and continuing without branching from a first extending end (E1) which is one end to a second extending end (E2) which is the other end in an extending direction, the heating wire having, between the first extension end (E1) and the second extension end (E2), a turn position (E3) to turn from a state in which the heating wire extends toward a distal portion side to a state in which the heating wire extends toward a proximal portion side, the heating wire being configured to generate heat over an entire length from the first extending end (E1) to the second extending end (E2) when an electric current flows therethrough, characterized in that an amount of the heat generated by the heating wire per unit area (ΔS) is smaller in a first heating region provided in the distal portion of the first jaw than in a second heating region provided in the proximal portion of the first jaw , the first jaw is divided in a longitudinal direction (C1, C2) into three or more regions different from each other in the amount of the heat generated by the heating wire per unit area (ΔS), and among the three or more regions, the amount of the heat generated by the heating wire per unit area (ΔS) is smaller in the regions located more distally. a first jaw which extends from a proximal portion toward a distal portion, and which has an outer surface exposed to an outside; a second jaw which extends from a proximal portion toward a distal portion, and which is openable and closable relative to the first jaw ; a treatment surface which is provided on the outer surface of the first jaw , and which faces the second jaw , the treatment surface being configured to treat the living tissue; and a heating portion including a heating wire , the heating wire being disposed in a range from the proximal portion to the distal portion in the first jaw , and continuing without branching from a first extending end (E1) which is one end to a second extending end (E2) which is the other end in an extending direction, the heating wire having, between the first extension end (E1) and the second extension end (E2), a turn position (E3) to turn from a state in which the heating wire extends toward a distal portion side to a state in which the heating wire extends toward a proximal portion side, the heating wire being configured to generate heat over an entire length from the first extending end (E1) to the second extending end (E2) when an electric current flows therethrough, characterized in that an amount of the heat generated by the heating wire per unit area (ΔS) is smaller in a first heating region provided in the distal portion of the first jaw than in a second heating region provided in the proximal portion of the first jaw , the first jaw is divided in a longitudinal direction (C1, C2) into three or more regions different from each other in the amount of the heat generated by the heating wire per unit area (ΔS), and among the three or more regions, the amount of the heat generated by the heating wire per unit area (ΔS) is smaller in the regions located more distally. <EOS>