An ultrasound system 1 includes: a display unit 34 that displays an acquired ultrasound image as a first image in an image display region; an operation unit 40 that includes a touch sensor disposed so as to be superimposed on the image display region and is used by a user to perform a touch input operation; a second image generation unit 37 that generates a second image indicating a partial image which corresponds to a predetermined region including a touch position of the user in the first image; and a second image display position determination unit 38 that determines a position different from the touch position in the image display region as a display position of the second image on the basis of the touch position. In a case in which the image display region is touched by the user, the second image is displayed at the determined display position so as to be superimposed on the first image.