Metal halide lamp, metal halide lamp operating device, and headlamp device for automobiles

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The present invention relates to a metal halide lamp substantially containing no mercury, a metal halide lamp lighting device using the same and an automotive headlamp apparatus using the same. And object of the invention is to provide such products in which a rapid rising of luminous flux is achieved. A metal halide lamp (MHL) according to the present invention has : a discharge vessel having an inner volume of C (cc) and having a pair of electrodes (2), (2) sealed in a hermetic vessel (1a) at opposite ends of a discharge space (1a) in the hermetic vessel (1a) at a distance of 5 mm or less; and a discharge medium containing xenon gas at 3 atmospheres or higher, a halide of sodium Na, and at least one of halides of scandium Sc and rare earth metals, the melting point of the halides being T (K), in which a lamp power in a stable state is 50 W or lower, and the formula (1) is satisfied : [in-line-formulae](H/C)×[R/(T/500)6]<3.11  (1), [/in-line-formulae] where the amount of the halide deposited on the electrodes when the lamp is off is H (mg), and the ratio of a maximum lamp power at the start of lighting to the lamp power in the stable state is R.