An ultrasound diagnostic apparatus includes: a controller for controlling a transmission circuit and a reception circuit to obtain reception data for measuring a sound speed and to obtain first reception data for producing a B mode image a sound speed map producer for producing a sound speed map for the inside of the region of interest based on the reception data for measuring a sound speed and an image producer for producing a B mode image based on the first reception data for producing a B mode image and second reception data for producing a B mode image, the second reception data for producing a B mode image being reception data for measuring a sound speed obtained by transmitting and receiving ultrasonic beams with forming transmission focuses at points having a depth closest to the given depth on sound rays passing inside the region of interest.
