An ultrasound diagnostic apparatus including: an ultrasound probe to acquire a received signal via transmitting and receiving an ultrasound to and from a subject an image generating section to generate an ultrasound image data based on the received signal acquired via said ultrasound probe an output image generating section to generate output image data in such a manner that the output image data becomes a predetermined output size, by performing an image size changing process with respect to the ultrasound image data a comparison image generating section to generate comparison image data by changing an image size of the output image data so that the comparison image data has an image size same as an image based on the ultrasound image data and an image correction section to perform correction of the output image data, based on a difference between the comparison image data and the ultrasound image data.
