A ring-shaped light emitting unit comprising a ring-shaped light guiding member having a light emitting surface which continues in a direction in which the ring-shaped light guiding unit extends, and a light guiding path for introducing light of a light source into the ring-shaped light guiding member which is continuously connected to part of an outer circumference of the ring-shaped light guiding member, wherein the outer circumference of the ring-shaped light guiding member excluding a light inlet portion is truly round. In addition, an inner circumference of the ring-shaped light guiding member is also truly round. A center of the inner circumference of the ring-shaped light guiding member is located closer to an open end of the light guiding path than a center of the outer circumference of the ring-shaped light guiding member.