A head-up display apparatus includes a display device for displaying various items of information and a combiner provided in front of an eye of a viewer in a visual field of the viewer, which combiner allows an outside image lying in the visual field to be passed through it and which reflects an image displayed by the display device so that the outside image passed (transmitted) through the combiner and the displayed image reflected thereby are integrated in the same visual field of the viewer, the combiner being configured to be of a substantially spherical shape with a concave surface facing the viewer, and the display device being provided in such a position that a display can be directly observable from the outside through the combiner.