A fluorescence emitting device is provided using a phosphor emitting a light by bombardment of an electron beam and having excellent luminance lifetime. The electron beam excited phosphor comprises a solid solution prepared by an AlN crystal or AlN solid solution crystal formed with at least Eu, Si and oxygen represented by the composition formula Eu.sub.a Al.sub.b Si.sub.c N.sub.d O.sub.e [Wherein a+b+c+d+e=1, and a, b, c, d and e satisfy the following conditions:0.00001.ltoreq.a.ltoreq.0.10.4.ltoreq.b.ltoreq.0.550.001.ltore- q.c.ltoreq.0.10.4.ltoreq.d.ltoreq.0.550.001.ltoreq.e.ltoreq.0.1].