A control apparatus characterized by including: a storage unit that stores operation management information; an application executing unit that transmits a signal for turning off the power source of a field instrument; a resetting unit that, based on the signal, instructs to suspend the power supply from the input/output modules; and an activating unit that instructs to resume the power supply from the input/output modules, based on an elapse of preset time during which the power supply from the input/output modules should be suspended.