A producing method for producing zirconia hollow particles in which a
zirconia powder mutually combines to form a porous shell layer thereby
constructing a hollow structure, the method being characterized in mixing
under a pressurized contact a resin powder and a zirconia powder of a
grain size smaller than that of the resin powder, thereby forming a
precursor by covering a surface of the resin powder with the zirconia
powder in a partially embedded state, and calcining the precursor to
expel the resin powder and to mutually sinter the zirconia powder.