The present invention is a drug solution administration device for locally administering a drug solution to a predetermined site, wherein: a distal end (Pos1) of an injection needle (33) of an injector (22) is irradiated with pulsed ultrasonic waves from a cavitation-generating ultrasonic irradiation unit (20), under the control of a cavitation-generating ultrasonic focal point control unit (30), while a predetermined site of a target organ (32) is being monitored with ultrasound images based on an ultrasonic echo signal coming from a monitoring-use ultrasonic irradiation unit (21). After confirmation of changes in tissue characterization at the predetermined site by a detection and imaging unit (26), a cavitation generation surveillance unit (25), and the like connected to a monitoring-use ultrasound sending and receiving unit (27), a control unit (31) performs a control such that a drug solution is locally administered to the predetermined site.
