A medical treatment device includes: a probe where ultrasound vibration generated by each ultrasound transducer is transmitted from the one end to other end of the probe a jaw portion configured to rotate around a central axis of the probe and a controller configured to: calculate outputs, which respectively drive ultrasound transducers, based on a rotation angle of the jaw portion and drive each of the ultrasound transducers by each of the calculated outputs. Each output is an output that sets a direction of vibration of the other end caused by ultrasound vibration generated by each of the ultrasound transducers to a direction from the central axis to the jaw portion with respect to a direction along the central axis.
