An ultrasonic probe unit is provided with an ultrasonic probe, and a fixation section adapted to fix the ultrasonic probe to a living body, the ultrasonic probe includes an ultrasonic device adapted to perform transmission and reception of an ultrasonic wave, a probe-side magnet, and a displacement mechanism adapted to adjust a relative positional relationship between the ultrasonic device and the probe-side magnet, and the fixation section includes a fixation surface to be fixed to the living body, and a fixation section-side magnet a relative position of which to the probe-side magnet is fixed to thereby fix the ultrasonic probe to the living body.
