An ultrasound diagnostic apparatus includes a transmission and reception circuit which electronically scans with a transducer array in an ultrasound probe for acquiring two-dimensional image data an image producer which produces a three-dimensional ultrasound image using the acquired two-dimensional image data while mechanically scanning with the transducer array in a direction substantially orthogonal to the array direction of the transducer array and a controller which, when the internal temperature of the ultrasound probe is equal to or higher than a first set value, controls the transmission and reception circuit such that a composite scan including two different electronic scans is performed.
