A photoacoustic apparatus includes a light source (1) generating multiple lights with different wavelengths, a converting element (3) receiving photoacoustic waves generated in a subject by the subject being irradiated by the multiple lights, first distribution obtaining means (4) obtaining property distribution based on optical absorption within the subject, for each of the mutually different wavelengths, using time-sequence reception signals each output from the converting element (3) for each of the mutually different wavelengths, second distribution obtaining means (5) obtaining, using multiple property distributions based on optical absorption for each wavelength, a concentration-related distribution of a substance of an object region of the subject, and statistical information obtaining means (6) obtaining statistical information indicating variance in distribution in at least part of the concentration-related distribution.
