PURPOSE: To produce a thin coating flake to form into a good magnetic powder material excellent in magnetic anisotropy by blending specified ratios of rare earth elements such as Nd, alloy elements such as Fe and Ti and B.

CONSTITUTION: Compositional elements composed of rare earth elements (R) of Nd, Pr, Dy or the ones selected from those by about 13 to 17 atomic %, about 75 to 80 atomic % Fe, one or more kinds of alloy elements (M) selected from the group of Ti, Zr, Hf, V, Nb, Ta, Mo, W, Mn, Ni, Co, Cu, Zn, Ga, C, Si and S by 0.5 to 3 atomic % and about 6 to 7 atomic % B are melted to form a thin coating flake by a single roll method. In this way, the tin coating flake of the R-Fe-M-B quaternary elemental alloy excellent in magnetic anisotropy can be obtd.