Abstract: A highly directional light source device, more specifically, a light emitting element electrically connected on a substrate to produce light, and one interior having a photon recycler with a reflective surface, covered and set on one side of this substrate, and an opening set in the center of the top of the cover which corresponds with the light emitting element, thereby allowing the light from the light emitting element to be directly emitted out the opening, and then to be reflected back to the light emitting element through the reflective surface of the photon recycler, and after light is reflected or refracted according to the structure of the light emitting element, again through the opening the light is emitted onto the photon recycler, thereby achieving increased Étendue of the highly directional light source device and achieving the goal of effective light emission.