An ultrasound diagnostic device includes a transducer array, a transmission drive unit that causes the transducer array to transmit an ultrasonic beam from the transducer array toward a subject, a reception signal processor that processes reception signals output from the transducer array having received an ultrasonic echo from the subject, an image producer that produces an ultrasound image on the basis of the reception signals processed by the reception signal processor, and a control unit that controls the reception signal processor such that the reception signal processor is operated in a power saving mode in which processing of the reception signals output from the transducer array is selectively stopped depending on a measurement depth.