To provide a sheet light source device, which overcomes problems of deteriorated luminance distribution and appearance and has more excellent and practical optical properties.

A sheet light source device includes a light guide body 11 having a light emitting face 14. A linear shape light source 15 is disposed on one or more side ends 12 and 13 of the light guide body 11. Also, in the light guide body 11, there is provided a light drawing-out device 20 which serves to scatter beam from the linear shape light source and to draw out the scattered light from a light emitting surface 14 of the light guide body 11. The light drawing- out device 20 is formed by patterning a protruded rough face 20a which was protruded from the surface of the light guide body 11 and became rough. The light drawing-out device 20 has a substantial major axis in a vertical direction to the light source 15.