A switch detector of an energy treatment device detects a switch from a gradually decreasing state to a gradually increasing state on the basis of a detection result of acoustic impedance. In a state where ultrasonic electric energy and high-frequency electric energy are simultaneously output from an energy source, a controller stops an output of the ultrasonic electric energy on the basis of a fact that the switch of the acoustic impedance from the gradually decreasing state to the gradually increasing state is detected, and stops an output of the high-frequency electric energy on the basis of the fact that high-frequency impedance reaches a set threshold.
