Provided is an object information acquiring apparatus including: a light source a controller that controls irradiation of light from the light source a detector that receives an acoustic wave generated from an object onto which light from the light source is irradiated a processor that generates characteristic information inside the object using the acoustic wave received by the detector and an acquirer that acquires the shape of the object, wherein the controller controls an irradiation area when light is irradiated from the light source onto the object, based on the shape of the object acquired by the acquirer.