An ultrasound diagnostic apparatus 1 includes a transducer array 2, a transmission unit 3 that transmits an ultrasonic pulse FP and an ultrasonic pulse SP having phases inverted from each other on the scanning line from the transducer array 2 multiple times, a reception unit 4 that acquires reception signals from an output signal of the transducer array 2, a quadrature detection unit 5 that performs quadrature detection on the reception signals to acquire IQ signal strings, a tissue velocity detection unit 6 that detects a velocity of a tissue in a subject based on the IQ signal strings, a phase correction unit 7 that corrects phases of the IQ signal strings, a pulse inversion addition unit 8 that adds IQ signals corresponding to the ultrasonic pulse FP and IQ signals corresponding to the ultrasonic pulse SP using the corrected IQ signal strings to acquire added signals, and an image generation unit 10 that generates an ultrasound image from the added signals.