A ring redundant communication path control method of causing, under a ring redundant communication path in which a plurality of transfer apparatuses (1A to 1F) are annularly connected by connecting two ports of a transfer apparatus to ports of transfer apparatuses adjacent thereto, respectively, and a frame transfer path for transferring frames in opposite directions is redundantly configured, a user to uniquely select the frame transfer path by setting at least one port among the ports, which annularly connect the transfer apparatuses (1A to 1F), as a first port that is closed even in a normal state of the ring redundant communication path, the method comprising, for each of the transfer apparatuses: a step (S6-1) of periodically transmitting an inspection frame for inspecting a communication path to each of the adjacent transfer apparatuses from each of the ports connected to each of the adjacent transfer apparatuses (1A to 1F); a step of detecting (S6-2), when the inspection frame transmitted from the adjacent transfer apparatuses is not received for a fixed time from a port connected to the adjacent transfer apparatus, a first failure, being a failure of the communication path in the port in which the inspection frame is not received, and transmitting (S6-3) a non-arrival notification frame, which notifies that the inspection frame has not arrived yet, from the port in which the inspection frame is not received to the adjacent transfer apparatus; a step of detecting (S6-12, S6-4), when the non-arrival notification frame transmitted from the adjacent transfer apparatus is received, a second failure, being a failure of the communication path in a port in which the non-arrival notification frame is received; a step of closing (S6-5), when a first and/or a second failure is detected in any one of the ports connected to the adjacent transfer apparatuses (1A to 1F), respectively, a second port in which the first and/or a second failure is detected and transmitting (S6-11) an open command frame which is generated by the transfer apparatus itself which detects the first and/or a second failure for commanding to open the closed first port from another port other than the closed second port; a step of judging (S6-15) whether or not the open command frame is received; a step of transferring (S6-26), when the open command frame is received, the open command frame from another port configuring a ring redundant communication path which includes the port in which the open command frame is received; and a step of opening the closed first port when the closed first port is the other port other than the closed second port, the port in which the open command frame is received, or the other port configuring the ring redundant communication path which includes the port. a step (S6-1) of periodically transmitting an inspection frame for inspecting a communication path to each of the adjacent transfer apparatuses from each of the ports connected to each of the adjacent transfer apparatuses (1A to 1F); a step of detecting (S6-2), when the inspection frame transmitted from the adjacent transfer apparatuses is not received for a fixed time from a port connected to the adjacent transfer apparatus, a first failure, being a failure of the communication path in the port in which the inspection frame is not received, and transmitting (S6-3) a non-arrival notification frame, which notifies that the inspection frame has not arrived yet, from the port in which the inspection frame is not received to the adjacent transfer apparatus; a step of detecting (S6-12, S6-4), when the non-arrival notification frame transmitted from the adjacent transfer apparatus is received, a second failure, being a failure of the communication path in a port in which the non-arrival notification frame is received; a step of closing (S6-5), when a first and/or a second failure is detected in any one of the ports connected to the adjacent transfer apparatuses (1A to 1F), respectively, a second port in which the first and/or a second failure is detected and transmitting (S6-11) an open command frame which is generated by the transfer apparatus itself which detects the first and/or a second failure for commanding to open the closed first port from another port other than the closed second port; a step of judging (S6-15) whether or not the open command frame is received; a step of transferring (S6-26), when the open command frame is received, the open command frame from another port configuring a ring redundant communication path which includes the port in which the open command frame is received; and a step of opening the closed first port when the closed first port is the other port other than the closed second port, the port in which the open command frame is received, or the other port configuring the ring redundant communication path which includes the port.