To emit the illuminating light in the front direction in a central part and in the central part direction on the side surface side and avoid reduction in a luminance level on the side surface side through effective use of emitting light by forming inclined faces of a projecting part of a prism surface at an equal inclination in a central part and a different inclination on the side surface side.

A light-scattering light conductive plate 12 is set so that the illuminating light emitting direction inclines to the central side of an emitting surface 12C in a side surface side area of an incident surface 12A, and reduction in a illuminance level on the side surface side can be avoided, even by the emission of the illuminating light by sharp directivity. It is formed so that the setting of an inclination α and β gradually changes as it proceeds to a side surface from a central part even in a pair of inclined faces 12E and 12F, and an unnatural change in a luminance level of the emitting light is avoided. Furthermore, the illuminating light is also emitted by correcting the directivity of the direction running along the incident surface 12A by a pair of inclined faces 12E and 12F repeatedly formed on the reverse 12B of the light-scattering light conductive plate 12, and afterwards, the directivity of the direction orthogonal to this is corrected with a prism sheet 5. Then, the emitting direction of the illuminating light is inclined to the central side as it proceeds to the side surface side, and the emitting light can be used effectively.