A relay device in a system in which a transmission signal of a base station is relayed via a plurality of relay devices, includes: a first antenna configured to receive the transmission signal; a second antenna configured to communicate a target relay device being a relay destination relay device for the transmission signal; a communication unit configured to perform notification of setting information of the first and second antennas to other relay devices including the target relay device, and communication for acquiring setting information of the other relay devices; and an analysis unit configured to analyze a cause of a relay status lower than a criterion when the relay status of the transmission signal is lower than the criterion.