An ultrasonic diagnostic apparatus in which degradation in calculation accuracy and increase in calculation time can be prevented while an ultrasonic image with high resolving power is generated by using appropriate acoustic velocities for respective regions within an object. The apparatus includes: a transmitting and receiving unit for processing reception signals a reception control unit for performing focusing processing based on acoustic velocity values to generate a sound ray signal an image generating unit for generating an image signal based on the sound ray signal a focusing determining unit for determining a degree of beam focusing in the focusing processing with respect to plural first regions and an acoustic velocity value correcting unit for obtaining acoustic velocity values with respect to the plural first regions and further obtaining acoustic velocity values with respect to plural second regions segmented in smaller regions than the plural first regions.
