A treatment apparatus includes an ultrasonic vibration source, an ultrasonic treatment portion which is configured to treat living tissue by ultrasonic vibration transmitted from the ultrasonic vibration source, and a micrograin feeder which is configured to supply liquid containing micrograins to between the ultrasonic treatment portion and the living tissue. Whole micrograins within the micrograin-containing solution has a grain size equal to or smaller than an amplitude of the ultrasonic vibration.