To provide a distributed control system (FCS) with which the simple evaluation of environment data is performed on a plant operation picture and required processing can be timely executed.

An environment sensor 4 measures the environment of install place of FCS 2 and outputs the measured result as the environment data. A limit setting means 101 sets a limit value to the environment data on the screen of display means 100 at an operation monitor station (HMI) 1 similarly to process data. A display control means 102 graphically displays the value of environment data on the screen of display means 100 at the HMI 1 similarly to the process data and graphically displays the limit value set by the limit setting means 101 together.