A photoacoustic apparatus includes a processing unit configured to obtain a first image data group corresponding to a first wavelength, obtain first position shift information corresponding to irradiation timing of the light having the first wavelength on the basis of the first image data group corresponding to the first wavelength, obtain a second image data group corresponding to a second wavelength different from the first wavelength, obtain second position shift information corresponding to irradiating timing of the light having the second wavelength on the basis of the second image data group corresponding to the second wavelength, and obtain third position shift information on the basis of the first position shift information and the second position shift information.
