An ultrasound diagnostic apparatus includes a connection section to which an ultrasound probe having an ultrasound transducer mounted therein is detachably connected, a transmission section that drives the ultrasound transducer of the ultrasound probe connected to the connection section by a transmission signal of a transmission frequency thereof, an echo signal creation section that creates a digital echo signal from an echo signal received by the ultrasound transducer, a signal processing section that carries out signal processing to the digital echo signal, a processing-speed changing section that changes an operation frequency of the signal processing in the signal processing section, and a change control section that controls change of the operation frequency.
