A control message relay apparatus is arranged between a switch that processes a packet(s) based on externally set control information and a control apparatus that sets the control information in the switch. The control message relay apparatus comprises a control information storage unit that stores control information received from the control apparatus and information indicative of a setting status of the control information in the switch; and a control information conversion unit that reflects a control content(s) received from the control apparatus in control information held in the switch based on a predetermined control policy(ies).