An ultrasound diagnostic apparatus includes a quadrature detection section configured to perform quadrature detection on reception radio-frequency data generated by a reception circuit to generate complex data, a frequency analyzer configured to perform a first frequency analysis using the complex data of a set number of sample points starting from a first start point and a second frequency analysis using at least one group of the complex data of the set number of sample points starting from a second start point that is different from the first start point, and to acquire a spectral signal corresponding to each pixel of a Doppler waveform image based on results of the first frequency analysis and the second frequency analysis, and a Doppler waveform image generator configured to generate the Doppler waveform image using the spectral signal.
