An ultrasonic diagnostic apparatus capable of obtaining information on a pressure gradient in a blood vessel based on only reception signals of ultrasonic echoes reflected within an object. The apparatus includes: an ultrasonic probe for outputting reception signals a measuring unit for measuring an inside radius of a blood vessel within the object and blood flow velocities in plural locations in a radial direction substantially at the same time based on the reception signals and a computing unit for computing a velocity gradient in the radial direction at an inner wall point of the blood vessel by differentiating the blood flow velocities measured by the measuring unit in the radial direction, and computing a pressure gradient at ends of a predetermined length of the blood vessel based on the computed velocity gradient, the measured inside radius of the blood vessel, and a predetermined viscosity of blood.
