PURPOSE: To obtain stable magnet powder having high magnetic performance at low cost by forming a coating layer on the surfaces of magnet powder acquired by pulverizing the ingot of an alloy to be easily oxidized of a rare earth intermetallic compound, etc. in the diluting solution of an organic metallic compound, such as a silane coupling agent, a titanate coupling agent, etc. and preventing oxidation.

CONSTITUTION: The ingot of an alloy having a composition of Sm(0.672 Co, 0.08 Cu, 0.22 Fe, 0.028 Zr)8.3 is solution-treated for 4hr at 1,170°C in an Ar gas atmosphere, post-rough crushing in which isothermal aging and cooling aging to 200°C from 800°C are combined is executed, and the roughtly crushed alloy is added into a diluting liquid in which a 0.1wt% organic metallic compound having polyethyoxydimethylsiloxane bonds and a 0.05wt% organic metallic compound having γ-aminopropyltriethoxysilane bonds are added and dispersed to 0.05wt% difuron, and adjusted and pulverized so that the center value reaches to grain size of 20μm, thus obtaining magnet powder. Difuron is removed while being agitated, organic metallic films are formed on the surfaces of magnet powder, and magnet powder is cured for 15min at 130°C, thus acquiring a hard anti-oxidizing film.