An ultrasound diagnostic system including an ultrasound diagnostic device adapted to transmit an ultrasound beam toward a subject from an array transducer, and to receive an ultrasound echo from the subject to create an ultrasound image, and a workstation connected to the ultrasound diagnostic device, the ultrasound diagnostic system comprising: a storage unit adapted to store a plurality of ultrasound images in past diagnosis of a plurality of subjects as past images, wherein the workstation has an input unit for allowing an operator to input various kinds of information, a workstation-side display unit, and a workstation-side control unit adapted to control display in the workstation-side display unit, and wherein, in a case where a routine test in which a plurality of parts of the subject are sequentially subjected to ultrasound diagnosis in accordance with a determined procedure is performed and in a case where information on the subject is input from the input unit, the workstation-side control unit is adapted to make the workstation-side display unit perform a first display in which a plurality of past images in a past routine test of the subject stored in the storage unit are displayed as a thumbnail list and then perform a second display in which one past image and a current image including an ultrasound image newly created in the ultrasound diagnostic device with respect to a part corresponding to the one past image are displayed side by side, the one past image on a past image region (32, 40, 43, 69) and the current image on a current image region (33, 41, 44, 70) adjacent to each other, in an arrangement order of the plurality of past images displayed as the thumbnail list in the first display, characterized in that the workstation or the ultrasound diagnostic device has a time setting unit adapted to set a transition time taken until the first display of the workstation-side display unit transitions to the second display, the workstation-side control unit is adapted to make the display in the workstation-side display unit automatically transition from the first display to the second display after elapse of the transition time set in the time setting unit from a time point when the first display is performed, and the workstation-side control unit is further adapted to make the workstation-side display unit display a next past image in the arrangement order of the first display on the past image region in the second display after the second display of the current image corresponding to the one past image is performed and to make the current image region blank until a current image corresponding to the next past image is created by the ultrasound diagnostic device and displayed on the current image region from a time point when the next past image is displayed on the past image region. a storage unit adapted to store a plurality of ultrasound images in past diagnosis of a plurality of subjects as past images, wherein the workstation has an input unit for allowing an operator to input various kinds of information, a workstation-side display unit, and a workstation-side control unit adapted to control display in the workstation-side display unit, and an input unit for allowing an operator to input various kinds of information, a workstation-side display unit, and a workstation-side control unit adapted to control display in the workstation-side display unit, and wherein, in a case where a routine test in which a plurality of parts of the subject are sequentially subjected to ultrasound diagnosis in accordance with a determined procedure is performed and in a case where information on the subject is input from the input unit, the workstation-side control unit is adapted to make the workstation-side display unit perform a first display in which a plurality of past images in a past routine test of the subject stored in the storage unit are displayed as a thumbnail list and then perform a second display in which one past image and a current image including an ultrasound image newly created in the ultrasound diagnostic device with respect to a part corresponding to the one past image are displayed side by side, the one past image on a past image region (32, 40, 43, 69) and the current image on a current image region (33, 41, 44, 70) adjacent to each other, in an arrangement order of the plurality of past images displayed as the thumbnail list in the first display, characterized in that the workstation or the ultrasound diagnostic device has a time setting unit adapted to set a transition time taken until the first display of the workstation-side display unit transitions to the second display, the workstation-side control unit is adapted to make the display in the workstation-side display unit automatically transition from the first display to the second display after elapse of the transition time set in the time setting unit from a time point when the first display is performed, and the workstation-side control unit is further adapted to make the workstation-side display unit display a next past image in the arrangement order of the first display on the past image region in the second display after the second display of the current image corresponding to the one past image is performed and to make the current image region blank until a current image corresponding to the next past image is created by the ultrasound diagnostic device and displayed on the current image region from a time point when the next past image is displayed on the past image region.