An ultrasonic diagnostic apparatus and a method having a highly-reliable elastic evaluation unit for tissues. The invention includes a signal processing unit that processes received data obtained after ultrasonic waves are transmitted and received to/from an inspection target through a probe. An ROI detection unit of the processing unit obtains a distance index indicating a region proper for an elastic evaluation based on brightness distribution of the received data obtained by transmitting and receiving first ultrasonic waves to/from the probe, and sets an ROI based on the distance index. Then, second ultrasonic waves are transmitted to the ROI to generate shear waves. An elastic evaluation unit calculates a shear wave velocity based on received data obtained by transmitting and receiving third ultrasonic waves in the ROI, and outputs the shear wave velocity and an elastic evaluation value of the ROI as a reliability index.