This invention employs an object information acquiring apparatus including a probe for receiving, as a received signal, an acoustic wave which is generated within an object irradiated with light and propagates on an object surface, and a processor for generating object information, which is information based on an internal optical characteristic value of the object, by using intensity of the received signal. The processor corrects the intensity of the received signal by using the reflectance upon the acoustic wave entering the probe which is calculated based on the angle of the acoustic wave entering the probe, and on the acoustic impedance and acoustic velocity of the object and the probe.