PURPOSE: To produce a fluorescencer for electroluminescent element which can realize the improvement of luminance and the prolongation of lifetime by stably accelerating the growth of parent fluorescencer particles during the primary growth to thereby make the particle diameters and shapes uniform in the formation of the fluorescencer by two-stage firing.

CONSTITUTION: The process comprises a primary firing step wherein a mixture comprising parent fluorescencer particles 14b, an activator and a coactivator/ grain growth accelerator 14a is fired at a high temperature to grow the particles into intermediate fluorescencer particles of a specified particle diameter and a secondary firing step wherein the intermediate fluorescencer particles are fired. The total amount of the accelerator 14a used in the primary step is 15-30mol%, based on the particles 14b.