An ultrasound diagnostic apparatus (1) includes an ultrasound probe (19), an image acquisition unit (8) that transmits an ultrasound beam toward a subject from the ultrasound probe (19) to sequentially acquire ultrasound images, a blood vessel detection unit (10) that detects a blood vessel included in the ultrasound image acquired by the image acquisition unit, a blood vessel discrimination unit (11) that discriminates whether the blood vessel detected by the blood vessel detection unit is a vein or an artery, and a discrimination execution deciding unit (15) that decides whether the blood vessel discrimination unit (11) newly executes discrimination with respect to the ultrasound image of a current frame based on a movement amount of the ultrasound probe or a change amount of the ultrasound image between frames.