An ultrasound diagnostic apparatus which performs diagnosis of a subject to be examined by using an ultrasound probe which emits ultrasound waves and receives the ultrasound waves reflected by the subject, includes a measuring section which measures a motion velocity of local tissue of the subject by using an ultrasound waves transmitted/received by the ultrasound probe, an acquiring section which acquires motion information representing a strain or displacement of the tissue on the basis of the motion velocity, and a calculating section which calculates a parameter value representing a change amount of motion of the tissue with a change in load on the basis of two pieces of motion information acquired by the acquiring section in two load states in which different loads are applied to the subject.
