| 摘要 |
There are provided a mercury-free metal halide lamp which suppresses occurrence of flickering of light emission, and is improved in light flux rising immediately after starting, and more practical and suitable for a headlight, and a metal halide lamp lighting device and a headlight using this. A metal halide lamp according to the present invention comprises: a translucent air-tight container having an inner volume which is not greater than 0.1 cc; a pair of electrodes sealed facing each other with an inter-electrode distance which is not greater than 5 mm in the translucent air-tight container; and a discharging medium containing a plurality of metal halogen compounds selected from a group of scandium (Sc), sodium (Na), indium (In), zinc (Zn) and a rare-earth metal and a rare gas but intrinsically not containing mercury (Hg), wherein a tube wall load is not smaller than 60 W/cm<SUP>2</SUP>, and a ratio Vo/Vl satisfies an expression 0.45<=Vo/Vl<=0.72, where Vo is an average lamp voltage for 0.3 to 2 seconds after starting, and Vl is an average lamp voltage in a stable state.
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