A treatment instrument (10) is provided with a first gripping member (124), a second gripping member (174) which is configured so as to be opened from and closed on the first gripping member (124), a heat release member (112), and a first heat transmission member (132). In a process wherein the first gripping member (124) and the second gripping member (174) change from a state wherein the first gripping member (124) and the second gripping member (174) are closed together to a state wherein the first gripping member (124) and the second gripping member (174) are opened from each other, a predetermined position between the closed position and the opened position is defined as a switching position, the region from the closed position to the switching position is defined as a first region, and the region from the switching position to the opened position is defined as a second region. In the first region, the first heat transmission member (132) causes the first gripping member (124) and the heat release member (112) to be in a non-thermally connected state, and in the second region, the first heat transmission member (132) causes the first gripping member (124) and the heat release member (112) to be in a thermally connected state.L'invention concerne un instrument de traitement (10) qui comprend un premier élément préhenseur (124), un second élément préhenseur (174) qui est conçu pour être ouvert par rapport au premier élément préhenseur (124) et fermé sur ce dernier, un élément de libération de chaleur (112), et un premier élément de transmission de chaleur (132). Dans un procédé dans lequel le premier élément préhenseur (124) et le second élément préhenseur (174) changent d'un état, dans lequel le premier élément préhenseur (124) et le second élément préhenseur (174) sont fermés ensemble, à un état dans lequel le premier élément préhenseur (124) et le second élément préhenseur (174) sont ouverts l'un par rapport à l'autre, une position prédéterminée entre la posit
