A light source apparatus is designed in accordance with an object, and following elements and phosphors are disposed in a casing, a first light emitting element that emits a light in a first irradiation mode, which is selected so that a light emission band has a portion that overlaps a first-specific-band, a first phosphor selected so as to include the first-specific-band in an excitation band and include a second-specific-band in a fluorescence-emission-band, a second phosphor selected so that an excitation intensity compared with the first phosphor is low in the first-specific-band, and high in a second-fluorescence-excitation-band at a short wavelength side in a second-irradiation-band and a fluorescence-emission-band includes the second-irradiation-band other than the second-fluorescence-excitation-band, and a second light emitting element that emits a light in a second irradiation mode, which is selected so that a light emission band is included in the second-fluorescence-excitation-band.