A treatment system includes an energy source apparatus and a thermal treatment tool configured to receive electrical energy from the energy source apparatus. The thermal treatment tool includes a thermally conductive member having opposed respective treatment and installation surfaces. A board being disposed on the installation surface and having respective longitudinal and widthwise directions. The board includes an electrically conductive wire having a conductive portion and a heat generating portion for generating heat when supplied with electric energy. The board is folded back at a folded point and is disposed on the thermally conductive member such that the heat generating portion of the electrically conductive wire facing the installation surface.
