PURPOSE: To easily extend the number of work stations as required by providing network transmissivity between a monitor control server and each monitor control client and between the monitor control client and a display window system.

CONSTITUTION: A monitor control server 6 sends and receives monitor control information 10 with a remote monitor control system via a gateway 1 and updates a current state of monitored device depending on the received monitor information and informs the detection of a state change to relevant monitor control clients (A)7, (B)8 as monitor information (A)11 or monitor information (B)13 when the state change is detected. The monitor control clients (A)7, (B)8 act like clients for the monitor control server 6 and window systems 51, 52 and establish a link between the monitor control server 6 and the window systems 51, 52 at the start and the request and reception of the monitor information are implemented and the clients make display request to the window systems 51, 52.