The invention provides a rare gas discharge fluorescent lamp device which is long in life and high in brightness and efficiency. The lamp device comprises a rare gas discharge fluorescent lamp including a bulb having rare gas such as xenon, argon or krypton gas enclosed therein, a fluorescent layer formed on an inner face of the bulb, a reflecting film formed on an inner face of the fluorescent layer, and a pair of electrodes located at the opposite ends of the bulb. The lamp device further comprises a power source for applying a voltage across the electrodes, and pulse voltage forming means connected between the electrodes and the power source for forming a dc pulse voltage from a voltage supplied from the power source. The dc pulse voltage thus formed is applied across the electrodes to cause the lamp to be lit. The pulse frequency of the pulse voltage and the enclosed gas pressure are determined depending upon the rare gas employed, and particularly where dc rectangular pulses are used, the duty ratio is also determined depending upon the rare gas employed.