1. An object information acquiring apparatus that acquires information inside an object by receiving an acoustic wave that has arrived from inside the object through a layer having an acoustic impedance that is different from that of the object, and analyzing the acoustic wave, the object information acquiring apparatus comprising: an acoustic wave probe that receives an acoustic wave and converts the acoustic wave into an electric signal; a whole image generation unit that generates a whole image, which is an image indicating information inside the object, based on the electric signal after the conversion; a partial image generation unit that extracts a partial image, which is a part of the whole image, from the whole image; and a similar image search unit that searches an area similar to the partial image, from the whole image.