PURPOSE: To prevent an increase in temperature of a lamp body and miniaturize the lamp body formed of plastics by forming an optical multilayered film which reflects infrared rays and permeates visible lights on the bulb surface of a lamp, and forming the lamp body by plastics.

CONSTITUTION: When a lamp 17 is lighted, among the lights emitted from a filament 20, visible lights are permeated through an optical multilayered film on the surface of a bulb 19, reflected by the reflecting surface 33 of a lamp body 6, and radiated from a lighting opening 7. On the other hand, infrared rays unnecessary for illumination are reflected into the lamp 17 by the optical multilayered film on the surface of the bulb 19, and prevented from radiating out of the lamp 17. Thus, the infrared rays transmitted from the lamp 17 to the lamp body 6 is reduced, whereby even the small lamp body made of plastics can be prevented from increasing the temperature.