A manufacturing method of a light-emitting button key includes a pressing step of pressing a metal plate and forming a button body opened in one direction; an adhesive coating step of coating an adhesive in the button body; an injection-molding step of injecting a synthetic resin formed of a transparent or semitransparent material into the button body in which an adhesive layer is formed by the adhesive; and a groove machining step of penetrating the button body and adhesive layer from an outside of the button body and thus forming a light transmission groove corresponding to a character, number or symbol. The light transmission groove is formed in the groove machining step is not passed through the penetration part, and the light emitted from the rear side of the button body is radiated to an outside through the penetration part and light transmission groove.