RELAY DEVICE

In order to allow a user to backup data, a backup system is used to transfer data from an information terminal to a backup device via a relay device. The information terminal includes a storing unit storing the data to be backed up, and includes a communication unit transmitting the data to the relay device and transferring condition information indicating a condition to be satisfied by the relay device. Further, the relay device includes (i) a storing unit storing information relating to transfer destination devices, (ii) a receiving unit receiving the data and the transfer condition information, and (iii) a transfer control unit selecting a transfer destination device that satisfies the condition indicated by the transfer condition information, and controlling transfer of the received data in accordance with the selection. The backup device includes a receiving unit receiving the data transferred by the relay device, and a storing unit storing the received data.