PURPOSE: To provide a method and jig for firing ferrite magnetic cores wherein the deformation of magnetic cores due to firing is controlled and the fabrication of the jig is facilitated.

CONSTITUTION: The firing jig 10 has a plurality of trenches (recesses) directly formed in the area 13 of contact with a ferrite magnetic core 1. The jig 10 also has a ring 12 which is changeable depending on the size of magnetic cores 1, and a support 11 for holding the ring 12. A plurality of trenches are formed in the contact area 13 in the rings 12. This uniforms the coefficient of friction throughout the contact area 13, and thus, the relative movement of the magnetic core 1 due to shrinkage during firing, which results in the less deformation of the magnetic core 1. The presence of a plurality of trenches, directly formed in the rings 12, facilitates the fabrication of the firing jig 10.