In ultrasonic imaging, a physically consistent value of blood flow velocity is measured in the vicinity of body tissues. The ultrasound imaging apparatus comprises a shape extraction part for recognizing shape data of biological tissues by using echo signals reflected from a test subject irradiated with ultrasonic waves, a flow velocity distribution acquisition part for detecting blood flow velocities in the vicinity of the tissues from the echo signals, and a velocity determination part for extracting velocity information desired by a tester (objective velocity information). The velocity determination part sets a model of the objective blood flow, and determines a velocity of actually measured velocity distribution consistent with velocity distribution estimated from the model.
