A rod-shaped light transmission body that has a plurality of prisms and converts light incident from a light source to linear light through the prisms to output the linear light, the prisms including a first prism having a function of totally reflecting the incident light to output the light from the rod-shaped light transmission body, and second and third prisms that are positioned on both sides of the first prism, each of the second and the third prisms having a function of transmitting and deflecting the incident light.