An image display device for displaying a combined image by combining an virtual image with an external object, has a reflective type hologram combiner having an optical power for forming a surface optically equivalent to the external object at a position different from the external object, an image display for displaying an image to be provided as the virtual image at the position of the surface formed by the optical power of the combiner, and a selection surface for selectively reflecting and transmitting an image light from the image display and an external light from the external object. In the image display device, the image light is reflected by the selection surface, reflected by the hologram combiner, transmitted through the selection surface, and thereafter directed to the pupil of an observer, while an external light is transmitted through the hologram combiner, transmitted through the selection surface, and thereafter directed to the pupil of the observer.