A light source comprising an excitation light source (110) for providing excitation light, and an optical wavelength conversion member disposed at a distance from the excitation light source. The optical wavelength conversion member comprises an optical wavelength conversion material (150) for converting the excitation light into stimulated light. The light source also comprises an optical-guiding member that allows the excitation light to be incident on the optical wavelength conversion material, and an optical-collecting member (130A) for collecting stimulated light originating from the optical wavelength conversion material. To separate the paths of the stimulated light and the excitation light, the etendue of the optical-guiding member is less than or equal to ¼ of the etendue of the optical-collecting member. This allows the optical-guiding member to draw in the excitation light while preventing the excessive escape of the stimulated light through the optical-guiding member. The advantages of the light source are that it can separate the paths of the excitation light and the stimulated light, the light path is simple, and the optical members are easy to manufacture.