A subject information acquisition apparatus includes: an acoustic wave detector which detects an acoustic wave which is generated from a subject by irradiating light and outputs a detection signal an amplifier which amplifies the detection signal which is output from the acoustic wave detector a gain control unit which changes a gain of the amplifier as time elapses, according to a gain control table, in order to correct a drop in intensity of the acoustic wave caused by attenuation of fluence inside the subject and a signal processing unit which obtains information inside the subject based on the signal amplified by the amplifier. Measurement under a plurality of measurement conditions, where at least fluence distribution inside the subject or a position of the acoustic wave detector differs, is possible, and the gain control unit changes the gain control table according to the measurement conditions.
