PURPOSE: To provide intermetallic compound magnet of high coercive force by adjusting alloy structure through aging treatment using a magnetic tool in preparation of alloy magnet essentially consisting of compound having a specified ratio of one or more rare earth element R to transition element group M which includes Co.

CONSTITUTION: A permanent magnet made of alloy RMz (z=6.8W9) (e.g. alloy represented by the formula) essentially consisting of a compound having a ratio 2:17 for one or more rare earth elements R (e.g. Sm) to transition element group M (e.g. Co) that contains Co is prepared under the following condition. The alloy RMz is melted and casted under Ar, then treated to be made uniform. The alloy is then rougly crushed to be followed by fine crush using a jet mill, etc. The formed powder is molded and sintered. The sintered product is subject to aging by use of a cylindrical non-inductive electric furnace on which a magnetic generating coil is wound.