A tuning device measures and displays a deviation between a fundamental frequency of a music signal and a standard reference frequency. The tuning device has a meter having a graduated display and a movable needle, one or both of which are provided with a fluorescent substance. An LED emits energy effective to cause the fluorescent substance to emit light to illuminate the meter display thereby making it easy to tune a musical instrument in poorly lighted or dark locations. The fluorescent substance of the graduated display may emit light of the same or a different color from that emitted by the fluorescent substance of the needle indicator.