An object information acquisition apparatus according to an embodiment of the present invention includes a plurality of transducer elements (002) each configured to transmit an acoustic wave to an object (000), to receive reflected waves reflected from inside the object (000), and to convert the reflected waves into a time-series reception signal； and processing means (007, 009) configured to perform frequency domain interferometry combined with adaptive signal processing by using the reception signals output from the plurality of transducer elements (002) and a reference signal so as to obtain acoustic characteristics at a plurality of positions located inside the object (000). The processing means (007, 009) is configured to switch the reference signal to another reference signal at least once in accordance with a target position located inside the object (000) while performing the frequency domain interferometry so as to obtain the acoustic characteristics at the plurality of positions located inside the object (000) .
