A subject information acquisition apparatus comprises a casing in which a transmissive member capable of transmitting acoustic waves and laser beams therethrough is provided a light irradiating unit disposed inside the casing so as to irradiate a subject with laser beams with the transmissive member interposed an acoustic wave probe disposed inside the casing so as to receive acoustic waves with the transmissive member interposed and a scanning mechanism disposed inside the casing so as to move the light irradiating unit and the acoustic wave probe in relation to the casing, wherein the casing is configured to be movable on the subject.
