The disclosure provides a means for simplifying the configuration of network connection even when a plurality of control apparatuses are connected in a network. A control apparatus for controlling an object under control includes a first network controller and a second network controller for exchanging data according to a first communication protocol, and a packet transferring part for outputting a duplicate of a packet received by the first network controller from the second network controller and outputting a duplicate of a packet received by the second network controller from the first network controller.