A structure of illuminating unit includes a point-like light-emitting device, having an optical axis. An initial-stage conoid-like reflective surface has a convergent opening end and a divergent opening end. The point-like light-emitting device is located at the convergent opening end and the optical axis is toward the divergent end for emitting light. The initial-stage conoid-like reflective surface and the optical axis include an initial-stage included angle. A final-stage conoid-like reflective surface has a convergent opening end and a divergent opening end. The convergent opening end of the final-stage conoid-like reflective surface is coupled with the divergent opening end of the initial-stage conoid-like reflective surface. The final-stage conoid-like reflective surface and the optical axis include a final-stage included angle. The initial-stage included angle is larger than the final-stage included angle.