A subject information obtaining device according to the present disclosure includes: first optical characteristic value distribution obtaining means (252) arranged to obtain a first optical characteristic value distribution based on a first detection signal obtained by detecting first photoacoustic waves generated by irradiating light in a first measurement state on a subject (130, 131)； second optical characteristic value distribution obtaining means (252) arranged to obtain a second optical characteristic value distribution based on a second detection signal obtained by detecting second photoacoustic waves generated by irradiating light in a second measurement state different from the first measurement state on the subject (130, 131)； and data processing means (253) arranged to obtain a similarity distribution based on the first optical characteristic value distribution and the second optical characteristic value distribution.
