The light emitted from a spot light source (45) is emitted at a linearly extending region by a wedge-like light conductor (47) and deflected by a prism sheet (50). This light is emitted in a direction perpendicular to a light incident surface (44a) of the light conductor plate (44) and has a directivity narrow in a widthwise direction of the light conductor plate (44). The light conductor plate (44) is formed, at its bottom surface, with a multiplicity of diffusion patterns (46) in a rectangular triangular form. The light reflected upon the diffusion pattern (46) is emitted perpendicularly to a light emitting surface (44b) of the light conductor plate (44). At this time, part of the light incident on the diffusion pattern (46) transmits through the diffusion pattern (46) whereby the directivity of emission light is narrowed in a lengthwise direction of the light conductor plate.