The present invention is directed to a light guide whose one or both sides are structured, a method and an apparatus for manufacturing the same. The present invention is also directed to an illuminating system using the light guide whose one or both sides are structured. The illuminating system comprises a light source part including a light source generating a light and an optical guide optically connected with the light source part for emitting a light inputted from the light source part to outside. The optical guide comprises a hollow outer pipe and a hollow inserted body inserted into the outer pipe, wherein its one side is extended in a substantially same direction as a longitudinal direction to the optical guide, and it is structured with a plurality of linear structures arranged side by side.