Mounting structure of an led and mounting method thereof

A method of mounting an LED unit to a support member while adjusting orientation of said LED unit, wherein said LED unit includes an LED, a lens element positioned immediately in front of said LED, and a collar positioned around said lens, and wherein said support member includes a through-hole through which said lens element of said LED unit is exposed and an annular portion surrounding said through-hole, said annular portion being in contact with said collar of said LED unit, said mounting method comprising:

• adjusting said orientation of said LED unit by making an annular contacting surface, which is formed on one of an inner peripheral surface of said annular portion as an annular concave surface and an outer peripheral surface of said collar as an annular convex surface, and an annular contacting portion, which is formed on the other of said inner peripheral surface of said annular portion and said outer peripheral surface of said collar, slide on each other while changing a relative contacting position therebetween;
• and
• fixing said LED unit to said support member while maintaining a state of contact between said annular contacting surface and said annular contacting portion after said LED unit is directed toward a desired direction.