Purpose is to enable communication with a vehicle installation installed in a vehicle in a manner that facilitates implementation of a security measure and with high sensitivity and at low cost. An in-vehicle communication system includes an interior light with communication function, a seat and a display device, the interior light with communication function including a LED configured to transmit information to the seat and the display device via visible light communication, and the seat and the display device including light receiving units configured to receive information transmitted from the interior light with communication function and control units configured to control themselves based on the information received by the light receiving units.