A method of manufacturing a light guide plate comprising the following the steps. First, a thin film with a transfer material layer thereon is provided. Thereafter, a molding machine having a molding cavity therein is provided. A thin film is disposed in the molding machine such that at least part of the transfer material layer is located inside the molding cavity. A light guide plate body is formed inside the molding cavity so that the transfer material layer is transferred onto the light guide plate body at the same time.