An apparatus includes a receiving unit configured to receive a photoacoustic wave that is generated when an object is illuminated with light and to output a first time-series received signal, and a processing unit configured to acquire object information using the first time-series received signal, wherein the processing unit acquires a second time-series received signal whose reception time is normalized with respect to the specific speed of sound by resampling part of the first time-series received signal, and acquires the object information using the second time-series received signal and the specific speed of sound.
