A treatment device applying energy to a biological tissue and treats it, includes: a first energy output portion disposed in one of a pair of holding portions and including a first operation region that removes the biological tissue as a treatment object, and a second operation region that is disposed around the first operation region and joins the biological tissues as the treatment objects when energy is applied to the first and second operation regions simultaneously and a second energy output portion configured to apply energy to the biological tissue, disposed in the other holding portion of the holding portions, and disposed away from the second operation region more than from the first operation region when the holding portions are closed to hold the biological tissue between the holding portions, wherein a pressing force to be applied to the biological tissue between the second energy output portion and the first operation region is higher than a pressing force between the second energy output portion and the second operation region.
