To provide a lens array sheet capable of efficiently condensing diffuse light such as the light from a LED light source or EL light source. The lens array sheet comprises a transparent base material, a plurality of light-receiving sections each consisting of a transparent right frustum which is provided on the surface of the base material and is tapered outwardly from the base material, and a plurality of condensing lenses disposed on the back of the base material so as to face the respective light-receiving sections. The side face of the right frustum forms a taper angle larger than 0.degree. and less than 15.degree. with the central axial line of the right frustum, and an aspect ratio (H/D) which is a proportion of the height (H) of the right frustum to the minimum length (D) of the cut surface of the right frustum is larger than 0, and no more than 10.