A backlight device has a light guide plate, a rotary member, a rotary drive mechanism for rotating the rotary member, a plurality of mercury-free fluorescent lamps, and a power feed control mechanism. Each of the mercury-free fluorescent lamps has an arc tube mounted on the rotary member so as to extend parallel to the rotary shaft, a mercury-free discharge medium consisting of a rare gas sealed within the arc tube, and first and second electrodes for exciting the discharge medium. The mercury-free fluorescent lamps respectively emit lights of different colors. The emitted light enters the light guide plate through its light incident face and emerges from its light emission face.