A collecting lens comprises a first surface and a second surface. Said first surface lens is defined as an opposite surface of said collecting lens from said second surface. Said second surface has a lens surface. Said lens surface includes a plurality of lens function surfaces. Each of said lens function surfaces is defined as part of a side surface of corresponding one of elliptical cones. A particular normal line which is arbitrarily selected from normal lines at respective points on said first surface and crosses one of said lens function surface is not parallel to a central axis of the elliptical cone corresponding to said lens function surface crossed by said particular normal line. Said central axes of the elliptical cones are not parallel to each other.