An ultrasound diagnostic apparatus includes a measurement position-orientation determination unit, a judgment unit and a property measurement unit. The measurement position-orientation determination unit determines a measurement target region for measuring a property of a vascular wall, based on a 3D image of a blood vessel generated from transverse tomographic images acquired by scanning of an ultrasound probe in a longitudinal direction, and also determines a measurement position and measurement orientation of the ultrasound probe for acquiring a longitudinal tomographic image including the measurement target region. The judgment unit judges whether a current position and current orientation of the ultrasound probe differ from the measurement position and measurement orientation respectively by no greater than a threshold value, and when judging affirmatively causes the apparatus to acquire the longitudinal tomographic image. The property measurement unit measures the property based on the longitudinal tomographic image.
