A light source apparatus wherein when the light source apparatus is designed in accordance with an object, a first light emitting element that emits a light in a first irradiation mode is selected so that a light emission band has a portion that overlaps a first specific band (S3), a first phosphor is selected so as to include the first specific band in an excitation band and include a second specific band in a fluorescence emission band (S4), a second phosphor is 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 (S5), a second light emitting element that emits a light in a second irradiation mode is selected so that a light emission band is included in the second fluorescence excitation band (S6), and the first light emitting element, the first phosphor, the second phosphor and the second light emitting element are disposed in a casing.
