There is provided a subject information processing apparatus including a first acoustic conversion element that receives an acoustic wave having a first frequency reflected inside a subject and converts the acoustic wave into an analog signal, a second acoustic conversion element that receives an acoustic wave having a second frequency generated when light is irradiated to a subject and converts the acoustic wave into an analog signal, an A/D converter that converts the analog signal into a digital signal, a data memory that retains the digital signal, and a controller that instructs the data memory to output the digital signal at a predetermined sampling frequency for each receiving axis.
