PURPOSE: To avoid the deviation of composition by preventing the solid dissolution of Zn and to eliminate the problems such as deterioration of characteristics and lowering of strength, in the calcination of a formed article of an Mn-Zn ferrite, by placing the formed article on a base plate or a case and calcining the article.

CONSTITUTION: Powders of Fe2O3, MnO and ZnO are compounded with each other at specific molar ratios, mixed with a binder and compression-molded to a prescribed form. The obtained formed article 1 of an Mn-Zn ferrite is placed on a base plate 2 made of zirconia or on a dish-shaped case 3 made of zirconia. It is inserted into a sintering furnace keeping the above state and calcined in nitrogen atmosphere, etc. A sintered Mn-Zn ferrite having low magnetic loss, high resistance and high strength can be produced by this process.