An ultrasonic irradiation device 10 includes: an ultrasonic irradiation pad 110 including at least two output elements for emitting supersonic waves with output strength in a range of 50±5 mW/cm2 to 110±5 mW/cm2 at output frequency in a range of 500±50 kHz to 800±50 kHz drive control device 11 that drivingly controls the ultrasonic irradiation pad 110 and fastening device 120 that fastens the ultrasonic irradiation pad 110 in a state of being in close contact with a forearm 50 of the living body, in which the fastening device 120 is formed into a deformable strip having a removable fixed portion 120a in an end portion.
