An ultrasound diagnostic device includes: a contour extraction unit extracting a first contour image from ultrasound images obtained from spatially-successive examination positions and each including an image of an organ, a contour image indicating a contour of the organ and extracted from the organ image; a specification unit receiving, from a user, specification information specifying a manual correction target ultrasound image and correction information indicating details of a manual correction performed with respect to a first contour image extracted from the manual correction target ultrasound image; and a contour correction unit correcting the first contour image extracted from the manual correction target ultrasound image according to the correction information. The contour extraction unit further extracts a second contour image from a target ultrasound image by using information indicating the corrected first contour image. The target ultrasound image differs from the manual correction target image.