PURPOSE: To set the depth length of a front core of a magnetic erasion head with high accuracy by having a process where the grinding is applied from the core holder member side for setting the depth length and a process where a back core is butted to the front core.

CONSTITUTION: The notchs 3 and 3 are formed at the ridge parts of both sides of the opening part of a groove 2 cut along the entire width of a core holder member 1 in its center lengthwise direction with approximately U-shaped sections. Then a center core 4 and side cores 5 and 6 are put into the groove 2 via gap spacers and unified together. Both a front core 10 and the member 1 are simultaneously ground into flat planes together with a cylindrical grinding applied from the side of the member 1. Thus a magnetic tape sliding face 11 is formed and a front core is obtained. While a back core 13 includes a center part 13a and side parts 13b and 13c. Then the bottom surface of the part 13a is set to the upper surface of the core 4 together with the bottom surfaces of both parts 13b and 13c set to the upper surfaces of both cores 5 and 6 respectively. Then a back case 16 is adhered to the core 10. Thus a magnetic erasion head is obtained.