A HUD apparatus is provided. The HUD apparatus is provided with: an optical source part having a light emission element; a condenser lens, which faces the optical source part, and collects light source light; a field lens, which further collects the light source light transmitted from the condenser lens side, and which projects light at a predetermined angle; and an image formation element, which forms an image when the light source light transmitted from the field lens side is inputted thereto, and which projects light of an image toward the windshield side. The field lens has a composite surface on at least one of the condenser lens side and the image formation element side, the composite surface having multiple continuous optical surfaces. The condenser lens has a diffusion part that diffuses the light source light.