PURPOSE: To provide a manufacture for getting a MnZn ferrite wherein gas replacement around the ferrite is facilitated with a small quantity of gas flow and eddy current loss is reduced, in the introduction of oxygen nitride mixed gas being performed during the baking of the MnZn ferrite.

CONSTITUTION: This is the manufacture of a MnZn ferrite by setting and baking a molded item 1, which includes 0.01-0.2wt.% CaO and 0.01-0.05wt.% SiO2 to the basic composition consisting of 50-65mol% Fe2O3, 23-40mol% MnO, and 5-27mol% ZnO in terms of oxides, in sealed baking sheaths 2 and 3, which have a gas introduction port 8 and exhaust ports 5.