In an apparatus for operating and monitoring a plant, a manipulating device provides the plant with manipulation signals for operating the plant. In response to information supplied from the plant and a manipulating signal of the manipulating device, a first display data producing device produces first display data needed for the operation of the plant changing every moment. On the basis of data supplied from the first display data producing device, a first display device displays information relating to the operation of the plant. In response to information supplied from the plant and a manipulating signal of the manipulating device, a second display data producing device produces data needed for monitoring the plant. On the basis of data supplied from the second display data producing device, a second display device displays information relating to the monitoring of the plant on a larger display screen than that of the first display device. Information displayed by the first display device and information displayed by the second display device complement each other and make it possible to accurately operate and monitor the plant.