To economically construct the system by making it unnecessary to duplex facilities, and to improve functioning efficiency by reducing the load of a central control center, and to improve reliability by surely transmitting abnormality information to a maintenance agent even when communication is turned to be defective.

Local monitor devices 7 set at a plurality of local monitor places R arranged so as to be distributed across a wide area are allowed to share a function for collecting data D including abnormality data announced from a data announcing device 2 set in an equipment facility P, and for registering the data D in a data server 3 of a central control center C and a function for informing a maintenance agent M of the abnormality information. On the other hand, the data server 3 of the central control center C is allowed to share a function for analyzing and managing the data of each of those equipment facilities P, and when communication from the data announcing device 2 to any local monitoring device 7 is turned to be defective, the communication is automatically switched to data message communication to another local monitoring device 7.