HEAD UP DISPLAY

PROBLEM TO BE SOLVED: To prevent the visualization of a clearly displaying virtual image from obstruction by the generation of ghost and external light in a small head up display capable of displaying the virtual image of an observing object on a proper position and preventing entrance of dust into internal part. SOLUTION: By changing the optical path of image displaying light L transmitted from the inside of a housing 5 through an exit port 5a by means of a combiner 2 in front of an observer E, the virtual image of an observing object is formed in front of the combiner 2. An optical path changing means 8 for changing the optical path of the image displaying light L is provided on the lower part of a transparent cover 9 covering the exit port 5a so that the image displaying light L travels at an oblique angle forward/upward after being transmitted from the exit port 5a. A relative arrangement between an image displaying light transmitting means 3 of the transparent cover 9 and the optical path changing means 8 is determined so that the image displaying light L whose optical path is changed by the optical path changing means 8 reaches lower side than the range of visual field of the observer E after being reflected on the side of the lower surface of the transparent cover 9.