This light source device includes one light emission unit from which light is emitted, plural light source units, a photo coupler, and a control unit. The plural light source units output outgoing lights with mutually differing wavelengths. The photo coupler connects the light emission unit and plural light source units. The control unit controls the plural light source units via a driver. Each of the plural light source units includes a light emitting element and a wavelength conversion unit. The wavelength conversion unit converts the wavelength of light output from the light emitting element, thus generating the outgoing light.