A superior high-frequency magnetic material having a smaller ratio (.mu.''/.mu.') of a real part .mu.' of permeability and an imaginary part .mu.'' of permeability in a high-frequency region and an antenna system using thereof are provided. The high-frequency magnetic material includes a substrate and a composite magnetic film formed on the substrate and made of a magnetic phase forming a plurality of columnar bodies whose longitudinal direction is directed in a direction perpendicular to a surface of the substrate and an insulator phase filling gaps of the columnar bodies. The magnetic phase contains at least one of Nb, Zr, and Hf, and Fe and B, is amorphous, and has in-plane uniaxial anisotropy of Hk2/Hk1.gtoreq.3 and Hk2.gtoreq.3.98.times.10.sup.3 A/m when a minimal anisotropic magnetic field in a plane parallel to the surface of the substrate is Hk1 and a maximal anisotropic magnetic field is Hk2.