An object information acquiring apparatus, comprises a photoacoustic image acquiring unit configured to generate a first image related to optical characteristics within the object； an ultrasonic image acquiring unit configured to generate a second image related to acoustic characteristics within the object； a region of interest designating unit configured to receive designation of a region of interest with regard to the first image； an image processing unit configured to perform image processing on the first image inside the region of interest and outside the region of interest, respectively, using different image processing parameters； and an image synthesizing unit configured to superimpose and synthesize the first image, which has been image processed, and the second image.
