PURPOSE: To quickly and exactly display the plant condition on a large number of display devices.

CONSTITUTION: Plant state supervisory equipment 1 is provided with a plant data receiving device 2 to receive plant data sent from a plant through a transmission line and plural plant data display device 3 connected by a network in order to display received data. The plant data receiving device 2 is provided with each data buffer 24 for display screen installed correspondingly to plural display screens to be displayed on the plant data display device 3, a display data distributing part 22 to select the data required for each display screen and store it in each data buffer for display screen, and a data distributing and transmitting part 27 to take the data of the display screen to be displayed out of the corresponding data buffer for display screen and send it to each plant data display device. Each plant data display device 3 is provided with a means for an operator to designate the display screen.