A link aggregation function and maintenance function by MPLS OAM. Identical entry information is stored in plural circuits IF which perform a LA setting. In this way, multiplexing to the same LSP is possible even with different IF. The first network IF is assumed to be OAM ACT, and the second network IF is set to OAM SBY (SBY). OAM frame insertion is performed only by an OAM ACT port. In this way, in an opposite MPLS transmission apparatus, it is possible to prevent CV frame reception above a specified number of frames. Further, a switch forwarding table is set to forward frames from the network side to the first network IF of OAM ACT. The second network IF which was set to OAM SBY does not perform fault detection by CV reception. In this way, incorrect detection of faults due to non-reception of OAM can be prevented.