An ultrasonic diagnostic apparatus capable of quantitatively obtaining a blood flow velocity unaffected by angle dependence. The apparatus includes: an ultrasonic probe including ultrasonic transducers for receiving ultrasonic echoes to output reception signals a first movement information calculating unit for calculating first movement information on movement of a mobile element in a sound ray direction within the object based on the reception signals a signal calculating unit for calculating azimuth direction component signals representing components of ultrasonic echoes in an azimuth direction based on the reception signals a second movement information calculating unit for calculating second movement information on movement of the mobile element in the azimuth direction within the object based on the azimuth direction component signals and a two-dimensional velocity calculating unit for calculating two-dimensional velocity information of the mobile element moving within the object based on the first and second movement information.
