To have a saturation magnetization, temp. coefficient of the saturation magnetization and dielectric loss suited for high frequency circuit components and reduce the magnetic resonance absorption half-width, by mixing Y, Gd, Fe, Al Mn and O at specified ratio and baking them.

The magnetic material is a baked compd. contg. elements expressed by (Y1-xGdx)8-y(Fe1-y-zAlyMnz)vO12 (0≤x≤0.4, 0≤y≤0.15, 0.002≤z≤0.016, 4.96≤v≤4.99). The proportion of the compsn. is 99 mol.% or more of the magnetic material which may contain Si, In, Sc, etc., at other elements and total content these elements is usually within 1 mol.% of the magnetic material. The saturation magnetization of the magnetic material and temp. coefficient of the saturation magnetization e.g. may be set within a range of 400-1780G and -0.10∼-0.35%/°C, respectively, and the magnetic resonance absorption half-width and dielectric loss can be reduced.