PURPOSE: To display excellent corrosion-resisting property, to extremely reduce the dimensional variation at high temperature, and also to display excellent magnetic characteristics by a method wherein the binder resin of prescribed quantity is compounded in rare-earth element-B-Ga-Co-Fe magnet alloy powder, a compression molding work and a hardening treatment are conducted on the obtained magnet alloy composition under the prescribed condition, and then electroplating is performed successively.

CONSTITUTION: A compression-molded body is obtained by compression-molding the magnet alloy composition which is formed by mixing magnet alloy powder consisting of 8 to 30 atomic % rare-earth element, 2 to 28 atomic % B, 0 to 3 atomic % Ga, 0 to 40 atomic % Co and the remaining part consisting of Fe, and 5 to 50vol.% thermosetting resin against the magnet alloy powder under the condition of the temperature of 70 to 250°C and the pressure of 1 to 12ton/cm2. Then, a hardening treatment is conducted on the compression- molded body at 50 to 250°C, and an electroplating is performed on the compression-molded body after the hardening treatment is finished.