An on-board signage system includes one or more vehicles, a display device configured to display an assigned image on a display area of each of the vehicles, and a signage controller, in which the signage controller is configured to function as an image database for storing a plurality of candidate images, a terminal database for storing identification information and owner information of a registered terminal, a terminal location acquiring unit configured to acquire location information of the registered terminal, and a selector that selects at least one of a travel route for the vehicle and an image to be assigned to the vehicle, based on the location information and the owner information of the registered terminal, and transmits the selected travel route or image to the vehicle.