Upon detection of a portable terminal positioned at a predetermined distance allowing wireless communication with an in-vehicle device, the in-vehicle device in an in-vehicle system performs a pairing process with respect to the detected portable terminal to establish wireless communication with the detected portable terminal. Thereafter, the in-vehicle device acquires an image and sound acquired by an application being executed on the portable terminal from the portable terminal, with which wireless communication has been established. The in-vehicle device converts acquired various types of data into an outputtable format of the in-vehicle device and outputs the converted data to at least one of a display unit and a speaker.