A light source apparatus is equipped with at least three light sources each having a predetermined wavelength interval and different central wavelengths. At least one multiplexing means having wavelength selectivity, for multiplexing light emitted from each of a first group and a second group of the light sources is provided, the first group of light sources including odd ordered light sources and the second group of light sources including even ordered light sources when counted in order of lengths of the central wavelengths thereof. Multiplexing means not having wavelength selectivity, for multiplexing light emitted from the first group of light sources and the second group of light sources is also provided.