PURPOSE: To reduce the evolution of heat owing to hysteresis loss and eddy current loss by laminating plural sheets of high magnetically permeable material having relatively high saturation magnetic flux density and high magnetically permeable materials having relatively low saturation magnetic flux density alternately thereby forming the magnetic core of an erasing head.

CONSTITUTION: A center core 1 and side cores 2a, 2b are formed of ferritic materials 8 of relatively low saturation magnetic flux density and "Sendust " materials 9 of relatively high saturation magnetic flux density, plural sheets of which are laminated and adhered alternately. The materials 9 are formed to roughly the same layer thickness as the thickness of the materials 8. The blank of the magnetic head is formed by placing the center core 1 mounted with a bobbin 5 at the center, butting and disposing the side cores 2a, 2b to and on both side surfaces of the core 1, and forming magnetic gaps 3a, 3b on the butt- mated surfaces thereof on the side where the face slide with magnetic tapes. The core 1 and the cores 2a, 2b are disposed so as to face the laminate of the materials 8 and the laminate of the materials 9 through the gaps 3a, 3b.