An ultrasonic photoacoustic imaging apparatus which includes a probe incorporating an 
array transducer having a plurality of transducers and an acoustic 
image generation unit that generates, based on a mixed 
signal obtained by converting an 
acoustic wave, in which an ultrasonic wave and a photoacoustic wave are mixed and making use of a difference between phase shift aspect of electrical signals of the ultrasonic 
waves from the same reflection source in the inside of the subject and phase shift aspect of electrical signals of the photoacoustic 
waves from the same generation source in the inside of the subject, an electrical 
signal reflecting the ultrasonic wave and an electrical 
signal reflecting the photoacoustic wave, and generates an ultrasonic 
image based on the electrical signal reflecting the ultrasonic wave and a photoacoustic 
image based on the electrical signal reflecting the photoacoustic wave.