An ultrasound diagnostic device to which an ultrasound probe is connectable, measuring an IMT of a vascular wall in a carotid artery, includes: a transmission-reception processing unit supplying a transmission signal causing the ultrasound probe to transmit an ultrasound to short-axis cross-sections along the carotid artery, and receiving a signal based on a reflected ultrasound and generating a reception signal for frames at each position a two-dimensional image generation unit generating two-dimensional images corresponding to the frames a bulb boundary detection unit measuring a perimeter or area of the vascular wall in each image, and detecting a boundary between a CCA and a CCA bulb from the perimeter or area and position information indicating a position where each image is acquired a ROI determination unit determining a ROI defining an IMT measurement range with respect to the boundary and an IMT measurement unit measuring the IMT within the images.
