An energy treatment instrument includes a first grasping piece, and a second grasping piece opening and closing relative to the first grasping piece and grasping a treated target between the first grasping piece and the second grasping piece. An actuation state of the energy treatment instrument is switched between a first mode in which the treated target is coagulated when a forceps does not exist in a predetermined range from a position where the treated target is grasped, and a second mode in which the treated target is coagulated when the forceps exists in the predetermined range.
