PURPOSE: To reduce the effect of a diamagnetic field by alternately laminating magnetic material layers and dielectric layers.

CONSTITUTION: A magnetic material layer 1 is manufactured by alternately laminating magnetic material layers 1 and dielectric layers 2, widths (a), (b) are determined from the viewpoint of manufacture or use, and a/c>100 and b/c>100 hold regarding the thickness (c). The magnetic field components of electromagnetic waves projecting in the direction of an (x) axis runs parallel with a Y-Z surface, a sheet surface, in the sheet of the magnetic material layer 1, and magnetic anisotropy in the sheet surface is reduced and magnetoplumbite group ferrite is employed.