To execute excellent control even by using a measuring unit of a long measurement cycle by measuring a state of a plant in a shorter cycle than the measurement cycle of the measuring unit.

Plural measurement units 10, 11 and 12 measure a process state for one measurement point 9 and also a control part 17 for controlling a data collection cycle of the measurement units is constituted inside a control device 16. Then, the control part 17 measures a state of a plant in shorter cycle than the measurement cycle of the plural measurement units 10, 11 and 12. That is, when the measurement cycle of the measurement device is defined as (m) seconds and the number of the devices defined as (n), the control part 17 performs activation of measurement start from a device 1, a device 2 to a device (n) in this order in every m/n second. Thus, it is possible to execute excellent control even by using the measurement unit of a longer measurement cycle.