To improve the luminance along the normal of a light projection surface by arranging a 1st lens film where fine unit prisms in a prismatic shape having a specific apex angle are arrayed adjacently so that prism ridges are at right angles to a linear light source and arranging a 2nd lens film so that prism ridges are orthogonal.

A lens film 10 is provided having its light incidence surface 14 on a light-tramsissive film 18 integrally while unit prisms 12 made of prismatic light-transmissive substance are arrayed adjacently in parallel so that one side of a triangle in the section of each prism form the light incidence surface 14 and ridges 12A are parallel to one another. The unit prisms 12 are an isosceles triangle having both base angles made equal in its main cut surface and the vertical angle α facing the surface 14 of light incidence is 80 to 90°. When the ridges 12A are made perpendicular to the length wise direction of incident light and a parallel light beam, the luminance which is perpendicular to it increases by approximately 8 to 13% on the light projection surface side as a compared with a case wherein the vertical angle α is 90°.