The present invention employs an object information acquiring apparatus that includes a plate configured to hold an object, a probe unit including a probe configured to receive an acoustic wave generated from the object, a tank configured to store matching liquid for acoustically matching the plate and the probe, a supplying unit configured to supply the matching liquid in the tank to a space between the probe unit and the plate, and a generating unit configured to generate property information of an inside of the object on the basis of the acoustic wave. The tank includes an aperture in a portion facing the plate, and the volume of the tank is larger than a sum of the internal volume of the supplying unit and the volume of the space between the plate and the probe unit.
