Generally, as the time for mechanical scanning of an acoustic wave receiver increases, the load on an examinee also increases. The present invention provides the calculation of a target speed at which an acoustic wave receiver is caused to move for the measurement of an acoustic wave, using data of an emission period of pulsed light and data of an interval between target measurement positions in a subject being examined. In addition, the acoustic wave receiver is caused to move so as to reach an initial target measurement position at the target speed at a time when initial pulsed light for measuring an acoustic wave is emitted. After the target speed has been reached, the acoustic wave receiver is caused to move at a uniform speed which is equal to the target speed.
