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.