A light source assembly includes first light sources emitting first light in a first wavelength range, second light sources emitting second light in a second wavelength range which is at least partially different from the first wavelength range, and an optical member on which light emitted from the first light sources and the second light sources is incident. A distance between adjacent first light sources, and a distance between adjacent second light sources is defined as an average pitch. The average pitch of the second light sources arranged in a specific direction, is larger than the average pitch of the first light sources arranged in the specific direction. The optical member has a reflectance with respect to the second light, which is larger than a reflectance with respect to the first light.