An object of the present invention is to increase freedom of selection of light sources in a photoacoustic apparatus. A photoacoustic apparatus includes: a light source which irradiates an object with beams of light of a plurality of wavelengths either simultaneously or at different time points； acoustic wave detecting means for receiving an acoustic wave generated at the object due to the irradiated beams of light, and converting the acoustic wave into an electrical signal； and signal processing means for acquiring characteristics information of the object based on at least the electrical signal.
