Image light emitted from an image emitting unit including a light source (1) or the like is introduced into a light guide (10), reflected by an incident-side reflection surface (12), and guided to an inside of a substrate (11). The image light propagates while being reflected by a first surface (11a) and a second surface (11b) of the substrate (11), and is emitted from the substrate (11) by being partially reflected by the outgoing-side reflection surfaces (13a to 13e) as half mirrors. A transparent plastic protective plate (15) is disposed with a distance “d” of 1 mm