A treatment apparatus to treat living tissues by applying energy to the living tissues, includes an energy source which supplies energy, a pair of holding faces to hold the living tissues, a joining treatment portion arranged in at least one of the holding faces to join the living tissues held between the holding faces, a detection portion which detects, through the joining treatment portion, living information of the living tissues by supplying energy to the living tissues through the joining treatment portion, a fluid feed portion disposed on at least one of the holding faces to feed fluid to the living tissues, and the fluid fed from the fluid feed portion guides energy to the living tissues, and a control portion to control a feed rate of the fluid fed from the fluid feed portion based on the living information of the living tissues detected by the detection portion.