A light guide unit has a cold mirror unit to guide display light toward a projection window. In an XYZ color system, a wavelength region between a wavelength at which a value of a color matching function Z is maximum and a wavelength at which a value of the color matching function Y is maximum is a first wavelength region, and a wavelength region between a wavelength at which a value of a color matching function Y is maximum and a wavelength at which a value of a color matching function X is maximum is a second wavelength region. A minimum reflectance of the cold mirror unit to the display light takes a minimum value among reflectances of the respective wavelengths in a corresponding wavelength region. The minimum reflectance in the second wavelength region is larger than the minimum reflectance in the first wavelength region.