To provide a monitor and control system capable of flexibly corresponding to a change in the connection of equipments including an I/O device and a peripheral device connected to a controller by a master monitoring device and reducing working load.

The monitor and control system has equipments including an engineering device 4 for constructing a system construction program on an off line, monitoring devices 1, controllers 2 and peripheral devices 12 and each monitoring device 1 loads down the system construction program obtained from the device 4 to the controllers 2, executes the monitor and control of a plant based on the system construction program and monitors/controls a change in the connection of equipments including the controllers 2. Each controller 2 detects an equipment to be additionally loaded or deleted, prepares a constitution changing equipment information profile related to the equipment to be added/deleted and informs the monitoring device 1 of the prepared profile.