An on-vehicle device, which is to be mounted on a vehicle, includes a wireless communication unit which is connected to a mobile terminal located within a communication range to perform wireless communication with the mobile terminal, and provides a service using the wireless communication in the wireless communication unit. The on-vehicle device further includes a parking determination unit which determines whether or not the vehicle is parked and a communication range changing unit which narrows, when the parking determination unit determines that the vehicle is parked, the communication range of the wireless communication unit such that the communication range is narrower than that before the parking determination unit determines that the vehicle is parked.