A display includes a case and a display source received in the case, and allows a virtual image of an image displayed on the display source projected on a windshield of a vehicle through an opening of the case to be superimposed on a foreground image through the windshield which is visually recognized at an eye point of the vehicle. A cover for the display is configured to prevent foreign particles from entering an inside of the case through the opening, and allows the image projected from the display source to pass therethrough. The cover has substantially a wedge cross section so as to align a substantially straight light path of direct light from an arbitrary point on the display source through the cover without reflection with a reflected light path of reflected light from the arbitrary point and reflected twice on inner surfaces of the cover.