Ultrafine particles of refractory oxides, SiO2, MgO, Al2O3, Fe3O4, Mg2SiO4, CaTiO3 and MgAl2O4, were prepared by the gas-evaporation method. Oxide materials were heated by a CO2 laser beam of output 100 W and their vapors were condensed in the gas environment of He, Ar or Xe of 3.5~670 Torr. Fractional vaporization did not occur except for MgAl2O4. Most of the particles were spherical with the diameter of about 100 Å for both of the amorphous and crystalline oxides. They usually stuck to one another and looked like a tangled chain of spheres. The maximum yield of the ultrafine particles was about 10 mg per min. Some applications of the refractory ultrafine particles were discussed especially in connection with earth science.