An ultrasound diagnostic device includes an ultrasound probe including plural 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 transmission frequencies of the ultrasound transmitted from the ultrasound probe or reception frequencies of the ultrasound received by the ultrasound probe； and a calculation unit that calculates an index for diagnosing a tissue characteristic based on a relationship between reception signals of at least two different ultrasound transducers for at least two different frequencies of the transmission frequencies or reception frequencies altered by the alteration unit.
