A treatment tool (10) includes a first gripping member (124), a second gripping member (174) configured to be opened and closed with respect to the first gripping member, a heat radiating member (112) and a first heat conductive member (132). A predetermined position between a closed state and an opened state is defined as a switching position in a process of changing the closed state to the opened state, a first region is defined as a region from the closed state to the switching position, and a second region is defined as a region from the switching position to the opened state. The first heat conductive member brings the first gripping member and the heat radiating member into a non-thermally contacted state in the first region, and brings the first gripping member and the heat radiating member into a thermally contacted state in the second region.
