PURPOSE: To prevent generation of crazing of magnetic cores and generation of peeling, etc., of magnetic metallic films at the time of formation and to improve the yield and reliability of products by forming sections of track width regulating grooves to a polygonal shape having ≥2 bent parts.

CONSTITUTION: The sections intersecting orthogonally with the longitudinal direction of the respective groove parts 11 of a pair of magnetic core half body blocks 12, 13 forming respective apertures 15 are formed to the shape having the three bent parts 21, 22, 23. Respective head chip are cut out of a pair of the magnetic head blocks at the time of forming the magnetic head. At this time, the stresses generated in a glass material 5 are relieved in the bent parts 21, 22, 23 and the durability to working stresses is greatly improved in consequence of the differences between the coeffts. of thermal expansion of the materials of the magnetic cores 1, 2, glass material 5 and magnetic metallic materials 4 which are the respective constituting elements of the magnetic head. Further, the effective overall stresses acting on the magnetic metallic films 4 formed in the respective track width regulating grooves are relieved and the peeling of the magnetic metallic films 4 is suppressed.