A rare earth permanent magnet is in the form of a sintered magnet body having a composition R.sup.1.sub.aR.sup.2.sub.bT.sub.cA.sub.dF.sub.eO.sub.fM.sub.g wherein F and R.sup.2 are distributed such that their concentration increases on the average from the center toward the surface of the magnet body, and grain boundaries having a concentration of R.sup.2/(R.sup.1+R.sup.2) which is on the average higher than the concentration of R.sup.2/(R.sup.1+R.sup.2) contained in primary phase grains of (R.sup.1,R.sup.2).sub.2T.sub.14A tetragonal system form a three-dimensional network structure which is continuous from the magnet body surface to a depth of at least 10 .mu.m. The invention provides R--Fe--B sintered magnets which exhibit a high coercive force.