A rod-shaped light guide which does not cause unevenness in color at the portion near an incident face is produced by injection-molding transparent resin such as acryl and its surfaces include a light-emitting surface, a bottom face, left and right sides and end faces. One end face opposes a light emitting unit, and light scattering patterns for scattering light incident from the end face are formed on the bottom face. The light scattering patterns are different in shape between a portion near the end face as the incident face and a portion away from the end face. The light scattering patterns formed at the portion near the incident face are composed of a large number of fine hemispherical concaves, whereas the light scattering patterns at the portion away from the incident face are composed of triangular grooves or half cylindrical grooves, and the axial direction of these triangular grooves or half cylindrical grooves coincides with the width direction (sub-scanning direction) of the bottom face on which the patterns are formed.