Provided is a system capable of reducing production costs. The system (on-board device) comprises an acquisition unit provided in a vehicle and comprising a camera unit that captures images and/or a microphone unit that captures sound; and an error detection unit that detects vehicle errors. The system sends the acquisition results from the acquisition unit, such as images and sound, to outside the vehicle in conjunction with a mobile information terminal provided in the vehicle, when the error detection unit has detected an error. Ideally, the mobile information terminal has a rechargeable battery unit and the acquisition unit and/or the error detection unit have power supplied thereto from the battery unit in the mobile information terminal, and can operate thereby. Also, the error detection unit ideally changes the error detection mode in accordance with the state of the battery unit in the mobile information terminal.