An error in a physical property value due to refraction of an ultrasonic wave is reduced, and thus the physical property value is calculated with high accuracy. A transducer of a transducer array transmits an ultrasonic beam to a subject placed in a predetermined imaging space, the transducer receives a transmission of the ultrasonic beam transmitted through the subject, and an image generating unit generates a transmission image based on the reception signal. The controller includes a focal length adjusting unit that adjusts a length between a focal position of the ultrasonic beam and the center of an imaging space to adjust a divergence angle of the ultrasonic beam.
