PURPOSE: To make it a permanent magnet of high magnetic properties without limitation on shape by forming one or more axial grooves on the inside periphery or the outside periphery of the diametrical anisotropic cylindrical permanent magnet having the composition of MO.nFe2O3.

CONSTITUTION: MO.nFe2O3 shall be included in the composition of the composition of a diametrical anisotropic cylindrical permanent magnet 20, and the ferrite powder is compressed and molded into cylindrical shape in the diametrical magnetic field. Next, at least one or more axial grooves 21 are provided on the inside periphery or the outside periphery of a compact to become this cylindrical magnet, and those are baked. The action of this groove absorbs, in the shape of deformation of the groove, tensile stress or compressive stress occurring in the cooling process during baking, and prevents the generation of cracks or breakage. This way, it can be made a permanent magnet excellent in magnetic properties and without limitation on shape.