A ceramic metal halide lamp includes a luminous tube an illuminating arrangement having at least two illuminators serially connected with each other and deposed inside the luminous tube and at least one retainer having at least contacting one end being contacted with an inner surface of the luminous tube to support the illuminators being stability located at a predetermined position inside said luminous tube, wherein the two illuminators are serially connected with each other along a central line of said luminous tube.
