PURPOSE: To improve a baking characteristic and an anti-reaction characteristic against immersion of substances of baked material by a method wherein more than one kind of substances selected from CaO, MgO, Y2O3 and CeO2 are added in a predetermined amount to stabilized zorconia raw material which is stabilized with a predetermined stabilizing agent and an amount of inclusion of impurities is highly purified to a value less than a specified weight.

CONSTITUTION: Substances of more than one kind selected from CaO, MgO, Y2O3 and CeO2 with 0.1 to 2.0wt.% and SiO2 of 0.1 of 0.8wt.% are added to a stabilized zirconia raw material with an amount of inclusion of stabilizing agents of more than one kind of CaO, MgO Y2O3 and CeO2 and impurities other than zirconia being 1.0wt.% or less is added in 0.1 to 2.0wt.% and SiO2 with 0.1 to 0.8wt.% is also added to form powder and then the powder is baked. With such an arrangement as above, its baking characteristic and anti-reaction against immersion of substances from the baked powder can be improved to make a high strength and a superior durability hardly producing any warp.