A treatment system includes a pair of holding members, a high-frequency energy output section, a heat generating section and a control section. At least one of the pair of holding members moves to the other holding member. The high-frequency energy output section and the heat generating section are provided on at least one of the holding members. The high-frequency energy output section exerts high-frequency energy to a living tissue to denature the living tissue, and collects the biological information of the living tissue. The heat generating section applies heat to it held between the holding members, generates the heat owing to the supply of the energy, and conducts the heat therefrom to denature the living tissue. The control section controls the output of the energy to the high-frequency energy output section and the heat generating section based on the biological information collected by the high-frequency energy output section.