A HUD 100 includes a R light source 12r, a G light source 12g, and a B light source 12b; collimating lenses 13r, 13g, and 13b that are arranged forwardly of the light sources; fly-eye lenses 16 and 17 that are arranged side by side on an optical path of light that exits from the collimating lenses; a light modulation element 20 that, based on image information, performs spatial modulation on light that has passed through the fly-eye lenses; a projection optical system 50 that projects image light onto a projection surface 7, the image light acquired by the spatial modulation by the light modulation element; photodetection elements PD1 and PD2 that are fixed to a portion of the fly-eye lens 16; and an image light control unit 40B that controls a brightness distribution of the image light based on a brightness of light detected by each of the photodetection elements.