Provided is a headup display apparatus that is capable of accurately outputting stable display light, a collimator lens, collimates image light, as parallel light, said image light having been outputted from a display means. A parallel light guide has a first surface, which has the parallel light from the collimator lens inputted thereto, and which reflects a part of the parallel light and transmits a part of the parallel light as transmitted light beams, and a second surface that reflects the parallel light to the first surface, said first surface and second surface being provided in parallel to each other. The parallel light guide outputs the transmitted light beams from the first surface, and the parallel light is inputted to the first surface at a predetermined angle.