PROBLEM TO BE SOLVED: To provide a photoacoustic apparatus, even when an output light quantity of a light source is changed with time, capable of reducing image irregularity generated therefrom.SOLUTION: The photoacoustic apparatus includes: a light source 2a for irradiating a subject with pulse light a detector 5 for detecting an acoustic wave generated in the subject 3 due to the pulse light a light quantity measuring device 8a for measuring an output light quantity of the light source 2a and a signal processing part 15 for acquiring information of the inside of the subject from the detection signal acquired from the detector 5. The signal processing part calibrates intensity of the detection signal so as to inhibit intensity fluctuation in the detection signal caused by a secular change in the output light quantity.SELECTED DRAWING: Figure 1
