PURPOSE: To easily obtain desired continuous change in the magnetic permeability in one process by changing the position of a shutter shield at the initial, middle and finish stages of the process of sputtering on a core half body.

CONSTITUTION: A soft magnetic material 8 such as Sendust and a Mn-Zn ferrite material 9 are mounted on a target 1 of a cathode sputtering device to produce a MIG magnetic head, and a shutter 2 is disposed perpendicular to the sputtering jet flow so that the shutter 2 can be moved. In the initial stage of sputtering, the soft magnetic material 8 is covered with the shutter 2 to deposit the ferrite material 9 to about 0.1μm thickness. In the middle stage, the shutter 2 is moved to the center position to form a mixture layer of the materials 8, 9 to about 0.5μm thickness, and in the finish stage, the shutter 2 is slid forward to cover the material 9 to form a layer of the soft magnetic material 8 to 2μm total thickness.