The invention has for its object the provision of an oxynitride fluorescent material has higher emission luminance than conventional rare earth element-activated sialon fluorescent materials. To this end, an oxynitride fluorescent material is designed in such a way as to contain as the primary constituent a JEM phase represented by a general formula MA1(Si6−zAlz)N10−zOz wherein M is one or two or more elements selected from the group consisting of La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb and Lu. For instance, this fluorescent material has a fluorescent spectrum maximum emission wavelength of 420 nm to 500 nm inclusive and an excitation spectrum maximum emission excitation wavelength of 250 nm to 400 nm inclusive.