To provide a compact and inexpensive display device excellent in maintainability.

A first hologram layer 13 and a second hologram layer 14 with which a plate-like combiner 3 is provided are arranged by leaving a space between them and inclined with respect to the outside surface of the combiner 3. Then, image display light L is emitted toward the layer 13. The light L is advanced in the combiner 3 along the outside surface thereof by being diffracted by the layer 13 and guided by the layer 14. Besides, it is emitted outside the combiner 3 from the outside surface thereof by being diffracted by the layer 14. Then, the light L and light L' transmitted through the combiner 3 so as to passed through the layer 14 are put together by the combiner 3.