A remote maintenance system includes a maintenance management apparatus connected to a user apparatus and a communication relay apparatus connected to a remote-controlled apparatus. The maintenance management apparatus transmits, to the communication relay apparatus, message data whose destination is unique identification information of a mobile communication network assigned in advance to the communication relay apparatus. The communication relay apparatus notifies the maintenance management apparatus of an IP address that is dynamically assigned to itself upon reception of the message data. The maintenance management apparatus transmits, to the communication relay apparatus, information on remote operation received from the user apparatus whose destination is the notified IP address. The communication relay apparatus relays, to the remote-controlled apparatus, the information on the remote control received from the maintenance management apparatus.