The present invention relates to a display device provided in a vehicle and performing communication with at least one processor provided in the vehicle. The display device includes a first display configured to output first light forming first visual information, a supporting unit configured to support a mobile terminal having a second display, and a light synthesizing unit configured to transmit either one of the first light and second light output from the second display and reflect another light, wherein the supporting unit is spaced apart from the first display with the light synthesizing unit interposed therebetween, and supports the mobile terminal so that the second light is directed to the light synthesizing unit.