Disclosed herein is a fluorescent light source including an yttria layer. Specifically, the current invention provides a fluorescent light source having high quality and a long lifetime, which can prevent a decrease in initial luminance of a fluorescent light source, including a fluorescent lamp, and resist the radiation of ultraviolet light and the permeation of mercury, which are the causes of deterioration of the fluorescent light source, so as not to decrease the luminance in proportion to the lighting time of the fluorescent light source, thus assuring both initial luminance properties and luminance properties after use for a long period of time. Such a fluorescent light source includes glass, a fluorescent material layer, and an absorbing layer composed mainly of yttria particles formed between the glass and the fluorescent material layer or on the inner surface of the fluorescent material layer. In addition, an yttria coating composition used in the fluorescent light source and a method of fabricating the fluorescent light source using the composition are also provided.