A link failure information transmission unit 130 of a transmission device 100 transmits link failure information indicating a fault in a link group to an opposing transmission device, upon detection of a fault in one or more of wired transmission lines belonging to any of link groups of the transmission device 100. Upon receiving the link failure information from the opposing transmission device, a link control unit 140 disconnects wired transmission lines included in a link group in the transmission device 100 corresponding to the link group in the opposing transmission device indicated by the received link failure information among the link groups of the transmission device 100. When the occurrence of a fault is notified in a system where transmission devices connected through an inter-transmission-device transmission line transmit signals of multiple wired transmission lines connected to the transmission devices, deterioration in communication efficiency of the entire system is avoided.
