An ultrasound diagnostic device detecting shear wave propagation velocity through push pulse transmission. The ultrasound diagnostic device includes: a push pulse transmitter that transmits a push pulse； a detection wave transmitter/receiver that, following the push pulse transmission, transmits plane wave transmission detection waves towards a region of interest (ROI) inside a subject and receives reflection detection waves from the subject, to generate receive signals sequentially； a displacement detector that detects subject tissue displacement occurring inside the ROI due to a shear wave； and a shear wave analyzer that detects a shear wave propagation velocity based on the subject tissue displacement. The transmission detection waves at least include transmission detection waves transmitted by the detection wave transmitter/receiver at a first transmission interval and transmission detection waves transmitted by the detection wave transmitter/receiver at a second transmission interval longer than the first transmission interval.
