An object information acquiring apparatus includes a light irradiating unit that radiates light to an object to generate a photoacoustic wave, a transducer that receives the photoacoustic wave, outputs a photoacoustic signal, transmits and receives an ultrasound wave beam to and from the object, and outputs an ultrasound echo signal, a determining unit that determines whether there is an object on an optical path from the light irradiating unit, and an image processor that generates internal image data of the object using the photoacoustic signal.
