A remote maintenance system comprising: a medical device which includes: a first power source; a first power source controller which controls an ON/OFF operation of the first power source; a checker which checks a check item; and a first communicator which transmits first information including a result of a check by the checker; and a relay unit which includes: a second power source; a second power source controller which automatically controls an ON/OFF operation of the second power source; and a second communicator which communicates with the first communicator and which receives the first information from the first communicator, wherein, after the first communicator transmits the first information to the second communicator, the first power source controller turns OFF the first power source, and after the second communicator receives the first information from the first communicator, the second power source controller turns OFF the second power source; and a maintenance center device, wherein the relay unit includes a third communicator which communicates with a fourth communicator included in the maintenance center device, and the third communicator transmits, to the fourth communicator, second information including the result of the check; wherein the maintenance center device changes and updates setting information of the relay unit and the medical device, through the first to fourth communicators; and wherein the check item includes at least one of a remaining amount of electric power of the first power source and an expiration period of an accessory of the medical device. a medical device which includes: a first power source; a first power source controller which controls an ON/OFF operation of the first power source; a checker which checks a check item; and a first communicator which transmits first information including a result of a check by the checker; and a first power source; a first power source controller which controls an ON/OFF operation of the first power source; a checker which checks a check item; and a first communicator which transmits first information including a result of a check by the checker; and a relay unit which includes: a second power source; a second power source controller which automatically controls an ON/OFF operation of the second power source; and a second communicator which communicates with the first communicator and which receives the first information from the first communicator, wherein, a second power source; a second power source controller which automatically controls an ON/OFF operation of the second power source; and a second communicator which communicates with the first communicator and which receives the first information from the first communicator, wherein, after the first communicator transmits the first information to the second communicator, the first power source controller turns OFF the first power source, and after the second communicator receives the first information from the first communicator, the second power source controller turns OFF the second power source; and a maintenance center device, wherein the relay unit includes a third communicator which communicates with a fourth communicator included in the maintenance center device, and the third communicator transmits, to the fourth communicator, second information including the result of the check; wherein the maintenance center device changes and updates setting information of the relay unit and the medical device, through the first to fourth communicators; and wherein the check item includes at least one of a remaining amount of electric power of the first power source and an expiration period of an accessory of the medical device.