Abstract: In an ultrasound diagnostic apparatus for forming a Doppler image, a plurality of partial regions are set within a scan region in which Doppler information is obtained. A partial scan operation is performed a plurality of times in a repetitive manner in each of the partial regions. In each partial region, a set of dummy transmitting and receiving beams is formed immediately before formation of the first set of transmitting and receiving beams. As the receiving beam in the first set of the transmitting and receiving beams is affected by the dummy transmitting beam, the receiving conditions can be unified over a plurality of sets of transmitting and receiving beams. A set of dummy transmitting and receiving beams may be provided immediately before the first partial scan operation or formation of a set of dummy transmitting and receiving beams in such a case may be omitted.