An ultrasound diagnostic device includes an ultrasound probe including ultrasound transducers that transmit ultrasound toward an imaging subject, receive ultrasound reflected from the imaging subject, and output ultrasound detection signals； an alteration unit that alters a transmission frequency of the transmitted ultrasound or a reception frequency of the received ultrasound, from a frequency for converting amplitudes, of the ultrasound detection signals outputted from the ultrasound probe, into an intensity distribution of brightnesses and displaying the distribution, to a frequency for carrying out diagnosis of tissue characteristics； and a calculation unit that calculates an index for diagnosing tissue characteristics, based on a relationship between received signals, at a time when the transmission frequency or the reception frequency is altered to a frequency at which diagnosis of tissue characteristics is carried out, at two or more different ultrasound transducers at the ultrasound probe.
