WE CLAIM:
1. A rear wheel position indicator comprising a light emitting unit for irradiating a
road surface on a side of a rear wheel of a vehicle with light, wherein
a light irradiation area by the light emitting unit is at least a planar area extending in a front-rear direction of the vehicle.
2. The rear wheel position indicator according to claim 1, wherein the light irradiation area by the light emitting unit is a planar area extending in the front-rear direction of the vehicle and extending in a left-right direction of the vehicle.
3. The rear wheel position indicator according to claim 1, wherein a shape of the light irradiation area by the light emitting unit is different from a shape of a light irradiation area by a marker light which may be mounted on a side surface of the vehicle.
4. The rear wheel position indicator according to claim 1, further comprising:
a traveling direction detecting unit for detecting a traveling direction of the
vehicle; and
a control unit for outputting an instruction to irradiate a road surface on a side of a left rear wheel of the vehicle with light if a traveling direction detected by the traveling direction detecting unit is a left direction, and outputting an instruction to irradiate a road surface on a side of a right rear wheel of the vehicle with light if the traveling direction is a right direction, wherein
the light emitting unit irradiates the road surface on the side of the left or right rear wheel of the vehicle with light according to the instruction output from the control unit.

5. The rear wheel position indicator according to claim 1, further comprising:
a road surface state identifying unit for identifying a state of the road surface; and
a control unit for outputting an instruction to switch light with which the road surface is irradiated according to a state of the road surface identified by the road surface state identifying unit, wherein
the light emitting unit switches the light with which the road surface is irradiated according to the instruction output from the control unit.
6. The rear wheel position indicator according to claim 1, wherein the light
emitting unit emits light in such a manner that a shape of the light irradiation area or a
color of the light changes with passage of time.