An ultrasound diagnostic apparatus comprises: an ultrasound probe, the ultrasound probe having a transducer array which transmits ultrasonic waves, receives an ultrasonic echo reflected by a subject, and outputs a reception signal according to the received ultrasonic waves, a signal processor which includes a reception amplifier having an amplifier amplifying the reception signal output from the transducer array and processes the reception signal, a selection unit for switching a current value of a bias current supplied to the amplifier, and a selection switch which performs a switching operation to switch the current value by the selection unit and a diagnostic apparatus body which produces an ultrasound image according to the reception signal processed by the signal processor of the ultrasound probe.
