A light source apparatus, capable of supplying white light including a predetermined wavelength band and a special light, which is light including the predetermined wavelength band and narrower in a band than the white light, includes: a first light source configured to emit light in a first wavelength band including the predetermined wavelength band, a second light source configured to emit light in a second wavelength band including the predetermined wavelength band, and a dichroic mirror configured to selectively transmit light in the predetermined wavelength band from one light of the lights in the first and second wavelength bands, selectively reflect light in a third wavelength band other than the predetermined wavelength band from the other light of the lights in the first and second wavelength bands, and mix and emit the light in the predetermined wavelength band and the light in the third wavelength band.