Abstract: This invention relates to a process for manufacturing R.sub.2 Co.sub.17 system permanent magnet alloys of rare earth(R)-cobalt(Co) intermetallic compounds. Sm.sub.2 Co.sub.17 alloy, in which R is samarium (Sm) with respect to intermetallic compounds whose stoichiometric composition is R.sub.2 Co.sub.17, possesses high saturation magnetization and high Curie temperature making it possible to obtain a high energy product. However, its permanent magnetization has not been practiced much at all because coercive force could not be obtained. This invention practices heat aging for 0.5-200 hours at 700.degree.-800.degree. C. in the heat treatment process of the sintered material of R.sub.2 (Co,Fe,M).sub.17 system (M is one or more than one elements of Ti, Cr, Mn, Ni, Cu, Zr, Nb, Hf, Ta, and W) and the coercive force is increased by carrying out this process in a magnetic field to achieve permanent magnetization.