PURPOSE: To enable an electroluminescent display element to efficiently and intensely emit a coloure required for colouring by applying element ions to be the main factor of emmission of the coloure to a base material composed of a specific IIIb-Vb ternary compound.

CONSTITUTION: A fluorescent layer 4 is comosed by applying element ions to be the main factor of emmission of a coloure to a base material composed of the IIIb-Vb ternary compound expressed by AlXGa1-XN (0<X<1) such as Al0.35Ga0.65N. As for the element ion to be the main factor of emmission of the coloure, one or two kinds or more selected from maganese ion and lanthanide ion are emmployed. An electroluminescent display element thus efficiently and intensely emits the coloure required for colouring.