To solve a problem that although an internally illuminating panel is practically used in which light is projected from the edge (end face) of an acrylic plate and total reflection is made to illuminate a board face, this device is designed and manufactured as an independent display device, and a similar display effect can not be achieved in a window glass without remodeling an existing window.

A projector includes: a light guide plate; a light source; and a light guide passage having a face in which one end is opposed to the light source and the other end is tightly adhered to the light guide plate. The whole light guide passage or at least a surface tightly adhered to the light guide passage is formed of a self adhesive transparent resin. The light guide passage and the light guide plate are attachable/detachable at faces mutually and tightly adhered as a boundary. Light emitted from the light source passes through the light guide passage interior, advances into the light guide plate by an incident angle equal to or more than a critical angle, and totally reflected in the light guide plate. This can be tightly adhered and fixed to the window glass by a removable way.