PURPOSE: To prepare ultrafine nonoxide particles in improved mass-productivity, by jetting and quenching a molten ceramic on a rotating body, reducing the quenched cooled brittle material with hydrogen, carbonizing or nitriding the material, and pulverizing the resultant material.

CONSTITUTION: A molten ceramic 1, e.g. an oxide, is jetted from a jetting port 3 of a nozzle pipe 2 on a rotating cooling body 4, quenched on contact therewith and formed into a flaky or powdery brittle oxide. The resultant flaky or powdery product is then reduced with hydrogen, carbonized or nitrided and pulverized to give the aimed ultrafine particles having a particle size ≤1μ with ease.