A vehicle-mounted display device includes an imaging unit, a traveling state determination unit, a hue discriminator, a color difference correction unit, and a display. The imaging unit captures an image of a surrounding of a vehicle. The traveling state determination unit determines whether the vehicle is traveling in a tunnel. The hue discriminator discriminates a hue of the image when the traveling state determination unit determines that the vehicle is traveling in a tunnel. The color difference correction unit corrects color difference information about the image in accordance with a discrimination result of the hue discriminator. The display displays the image corrected by the color difference correction unit.