Bacteria, viruses, and the like can be killed by irradiating portions to be treated on the surface of the skin of a person to be treated and in the body thereof with ultrasonic waves. An ultrasonic treatment device comprises a treatment bath (11) for accommodating a medium, a first ultrasonic generation element disposed at a predetermined position in the treatment bath (11), and a vibrator unit (34) disposed so as to be movable in the treatment bath (11). The vibrator unit (34) is provided with a housing which forms a closed chamber with a predetermined portion serving as a contact portion that is brought into contact with a portion to be treated, and a second ultrasonic generation element which is attached to the contact portion in the chamber and on the back surface of which a hollow portion is formed. Not only bacteria, viruses, and the like can be killed by irradiating the portion to be treated on the surface of the skin with ultrasonic waves by driving the first ultrasonic generation element, but also bacteria, viruses, and the like can be killed by irradiating the portion to be treated in the body with ultrasonic waves by driving the second ultrasonic generation element.
