A remote control system comprising: a vehicle-mounted device; a mobile terminal; and a server, wherein the remote control system is configured such as to allow an application unit operating on the mobile terminal to be remotely controlled by the vehicle-mounted device, wherein the mobile terminal includes: the application unit, and a mobile-terminal vehicle-internal communication unit for communicating with the vehicle-mounted device; wherein the vehicle-mounted device includes: a vehicle-mounted-device input control unit, a vehicle-mounted-device display control unit, a vehicle-mounted-device vehicle-internal communication unit for communicating with the mobile terminal, a vehicle-mounted-device input switching unit for switching a transmission destination of output from the vehicle-mounted-device input control unit to the mobile terminal, and a vehicle-mounted-device output switching unit for switching output directed to the vehicle-mounted-device display control unit from display output from the vehicle mounted device to output from the application unit, wherein the mobile terminal is configured: to receive identification data from the vehicle-mounted device, to acquire, when the application unit is in operation, identification data for specifying the vehicle-mounted device, the mobile terminal, and the application unit, and to transmit the identification data to the server, to acquire from the server a setting file and/or a program for realizing the vehicle-mounted-device input switching unit, the vehicle-mounted-device output switching unit and the vehicle-mounted-device vehicle-internal communication control unit, the setting file and/or the program being determined by the combination of the identification data of the vehicle-mounted device, mobile terminal, and application unit, and to transmit the setting file and/or the program to the vehicle-mounted device, wherein the vehicle-mounted device is configured to set and/or install the setting file and/or the program as transmitted from the mobile terminal. a vehicle-mounted device; a mobile terminal; and a server, the application unit, and a mobile-terminal vehicle-internal communication unit for communicating with the vehicle-mounted device; a vehicle-mounted-device input control unit, a vehicle-mounted-device display control unit, a vehicle-mounted-device vehicle-internal communication unit for communicating with the mobile terminal, a vehicle-mounted-device input switching unit for switching a transmission destination of output from the vehicle-mounted-device input control unit to the mobile terminal, and a vehicle-mounted-device output switching unit for switching output directed to the vehicle-mounted-device display control unit from display output from the vehicle mounted device to output from the application unit, to receive identification data from the vehicle-mounted device, to acquire, when the application unit is in operation, identification data for specifying the vehicle-mounted device, the mobile terminal, and the application unit, and to transmit the identification data to the server, to acquire from the server a setting file and/or a program for realizing the vehicle-mounted-device input switching unit, the vehicle-mounted-device output switching unit and the vehicle-mounted-device vehicle-internal communication control unit, the setting file and/or the program being determined by the combination of the identification data of the vehicle-mounted device, mobile terminal, and application unit, and to transmit the setting file and/or the program to the vehicle-mounted device,