An ultrasound diagnostic apparatus, which transmits an ultrasonic wave toward a subject by an ultrasound probe, produces ultrasound image data based on obtained reception data by a diagnostic apparatus body, and displays an ultrasound image, includes a dilation processor which performs dilation processing on the ultrasound image data based on a dilation radius to produce dilated image data, an erosion processor which performs erosion processing on the ultrasound image data based on an erosion radius different in magnitude from the dilation radius to produce eroded image data, a difference processor which calculates difference between the dilated image data and the eroded image data to produce difference image data, and an edge enhancer which performs edge enhancement processing on the ultrasound image data based on the difference image data to produce edge enhanced image data.