The subject invention provides a thin and flexible light guide element, which comprises a first optical layer composed of a flexible transparent material; a second optical layer formed on the lower side of the first optical layer and having a light-adjusting structure to change the light path; and a third optical layer formed on the upper side of the first optical layer and having a convex-concave structure to homogenize the light emitted from the first optical layer, wherein the first and second optical layers have different refractive indices.