An ultrasonic diagnostic apparatus includes: a first reference beam generating unit generating a first reference beam from DAS signals calculated in an N-th frame a second reference beam generating unit generating a second reference beam from a DAS signal calculated in an (N−1)-th frame, the DAS signal calculated in the N-th frame, and another DAS signal calculated in an (N+1)-th frame an attenuation coefficient calculating unit calculating, based on the first reference beam and the second reference beam, an attenuation coefficient to be multiplied by the DAS signals calculated in the N-th frame and a beamforming unit generating and providing a beamformed signal generated for a reference scan line in the N-th frame by multiplying a DAS signal calculated in the N-th frame by the attenuation coefficient.
