A thin-film electroluminescence device comprises a plate-like transparent electrode formed on a transparent substrate. A first insulating layer is formed on the transparent electrode. A second insulating layer is mounted on an electroluminescent layer made of ZnS:Mn and formed on the first insulating layer. A plate-like back electrode is provided on the second insulating layer. The first and second insulating layers are each made of gadolinium oxide of a purity level of over 99.9% and have a thickness of 0.05 to 0.8 mu m.