In the ultrasound diagnostic apparatus, the ultrasonic wave transmitter/receiver transmits and receives an ultrasonic beam to a subject to generate reception data using ultrasonic wave transmission/reception elements arranged in one direction the delay correction unit corrects a delay time of the reception data to align a phase of the reception data the reception aperture range determination unit determines a reception aperture range of reception data, which is used when producing an ultrasound image from reception data after correction of the delay time, based on a signal value of the reception data after correction of the delay time in an arrangement direction of the ultrasonic wave transmission/reception elements and the image producer produces an ultrasound image by performing phase matching addition of the reception data after correction of the delay time corresponding the reception aperture range and performing data processing.
