An ultrasound diagnostic apparatus including: a tomogram forming means forming a tomogram of a diagnosis portion of an examinee by transmitting/receiving an ultrasound wave to/from the examinee via an ultrasound probe; color Doppler image forming means forming a color Doppler image based on a Doppler signal obtained from the diagnosis portion; image processing means performing image processing on the tomogram and the color Doppler image; and display means displaying images obtained by the image processing means, the tomogram and the color Doppler image being color displayed on the display means, wherein the image processing means causes the color Doppler image to be displayed transparently.