Various embodiments provide a lateral reflector, wherein the lateral reflector has a bottom opening, a light source arranged on a base plate can be accommodated in the bottom opening; a reflecting surface is arranged on two opposite sides of the light source in the lateral reflector, and the reflecting surface is configured to reflect a light emitted from the light source and arriving at the reflecting surface, so that the light arriving at the reflecting surface is deflected toward a direction that is parallel to the opposite sides. Various embodiments further provide an array of such lateral reflectors. Further, various embodiments disclose a lamp unit and a lamp containing such lateral reflector, and puts forward a method for producing such lateral reflector.