An ultrasonic irradiation device according to the disclosure includes an ultrasonic transducer for external application of HIFU, which is focused ultrasound, to a body surface； and an optical imaging member or camera that takes images of part of the body surface corresponding to an ultrasonic irradiation target area. An irradiation position guide or a marker is located on the body surface, the marker is detected by the camera, and position and irradiation angle of the ultrasonic transducer are controlled based on information about a position of the marker. This makes it possible to direct a therapeutic transducer to a proper irradiation position, and monitor body surface condition during ultrasonic irradiation.
