PURPOSE: To improve operatability and movability through preventing over weight distribution on a front wheel through concentrating weight of a headlamp device near the center of gravity of a bicycle body by transferring the light of a light emission part arranged near the middle part of the bicycle body toward the headlamp arranged near the front wheel via optical fiber.

CONSTITUTION: In a light emission part 1, a super small-sized metal halide lamp 2, a converging mirror 4 for converging the light emitted from the lamp 2, a lamp switching-on circuit 5 having a light quantity adjusting shutter and a pulse circuit for start, and a constant energy source 6 are provided and received in a sealed case 7. On the other hand, a body case 12 and a small-sized plastic lens 13, which projects the light of the lamp 2 at the front side of the body case 12, are provided in the light projecting part 11. The light emission part 1 is arranged almost at the middle of a bicycle body 21, and only the light projecting part 11 having the small-sized plastic lens 13 is attached to the front part of the motor bicycle body 21. Thus, it is possible to prevent the over weight distribution on the front wheel, and to improve the operatability and movability.