A Fresnel lens sheet has an entrance surface (1a) and an exit surface (1b). A plurality of prisms (2) each having a refraction surface (3) and a total-reflection surface (4) are formed on the entrance surface (1a). Light rays projected by a light source (M) disposed on the side of the sloping refraction surfaces (3) onto the entrance surface (1a) are refracted at the refraction surfaces (3), and the refracted light rays are totally reflected by a total-reflection surfaces (4) in a direction substantially perpendicular to a sheet surface (1c). Angles (.alpha.) between the refraction surfaces (3) and the total-reflection surfaces (4) corresponding to the refraction surfaces (3) of all the prisms (2) are substantially equal to each other. The angle .delta. between the refraction surface (3) of the prism (P2) farthest from the light source (M) and the sheet surface (1c) is approximately equal to a right angle.