Disclosed are an ultrasound diagnostic apparatus and an ultrasound image producing method capable of producing a spatial compound image with reduced artifacts. Reception data of frame images is repeatedly acquired in a data acquisition cycle of four frames such that, of three frame images for use in producing a spatial compound image, the angle difference in steering angle between two frames for which the acquisition of reception data is most temporally separated is smaller than a maximum value among the angle differences in steering angle between two frame images among three frame images having different steering angles, and each time reception data of two frame images or reception data of another two frame images is acquired, three frame images sequentially produced based on reception data for three frames sequentially acquired hitherto are synthesized to produce a spatial compound image.
