In photoacoustic imaging, a subject information obtaining apparatus and a method for obtaining information regarding a subject that can accurately obtain an optical characteristic value are provided. A subject information obtaining apparatus according to the present invention includes a signal processing unit that includes a setting unit that sets certain sensitive regions corresponding to a plurality of acoustic wave detection elements on the basis of sensitivity distribution of the plurality of acoustic wave detection elements, an initial sound pressure obtaining unit that obtains initial sound pressure in a region of interest without using a detection signal corresponding to the region of interest obtained by an acoustic wave detection element whose certain sensitive region does not include the region of interest, a light intensity obtaining unit that obtains a value of integrated light intensity in the region of interest on the basis of detection signals used by the initial sound pressure obtaining unit, and an optical characteristic value obtaining unit that obtains an optical characteristic value in the region of interest using the initial sound pressure obtained by the initial sound pressure obtaining unit and the value of the integrated light intensity obtained by the light intensity obtaining unit.
