PURPOSE: To provide a rare earth iron based permanent magnet possessing a strong residual magnetic flux density and a strong coercive force, as well as a magnetization curve superior in rectangularity.

CONSTITUTION: A rare earth iron-boron based permanent magnet is composed of a sintered body which is prepared by the addition of, parts by weight, 0.01-1.0 zinc oxides and 0.1-2.0 of one or two, or more, types of elements selected from inorganic oxides: namely, Al2O3, SiO2, TiO2, V2O3, Cr2O3, MnO2, Fe2O3, CoO, NiO, CuO2, Ga2O3, GeO2, ZrO2, Nb2O5, MoO3, SnO2, Sb2O5, HfO2, Ta2O5, WO3, and Bi2O3, into 100 parts by weight of rare earth iron-boron alloy expressed by the equation of RxByCozFe100-x-y-zMw, wherein R is a rare earth element, and M represents one or two, or more, types of elements selected from Al, Si, Ti, V, CR, Mn, Ni, Cu, Zn, Ga, Ge, Zr, Nb, Mo, Sn, Sb, Hf, Ta, W, and Bi. The factors of the equation are defined, in atomic percent, as 8≤X≤30, 2≤Y≤28, 0≤Z≤20, and 0≤W≤4.0. And the prepartaion method of the above magnet is provided.