In a plant monitor and control system which includes a large display which displays plant monitor and control information items, and a navigation display terminal by which a touch input operation can be performed, an overall display screen of the large display is displayed on the navigation display terminal, and the display screen of the large display is expanded and displayed on the navigation display terminal in a state where the display screen of the large display, which is displayed on the navigation display terminal, is a base point, and minute information items of devices, which are displayed in a display screen of the navigation display terminal, are displayed.