A method of manufacturing a rare earth permanent magnet

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PROBLEM TO BE SOLVED : To provide an R-Fe-B-based sintered magnet that has high productivity, high performance, uses a little amount of Tb or Dy, and has an increased coercive force while suppressing decrease in remanent flux density by use of a powder mixture of alloy powder mainly containing intermetallic compound and an oxide of a rare earth element in a material for application and diffusion on a sintered magnetic body, and a method for producing the same.SOLUTION : In a method for producing a rare earth permanent magnet, heat treatment is performed on a sintered magnetic body at a temperature of the sintering temperature or below of the sintered magnetic body in a state where a powder mixture is disposed on a surface of the sintered magnetic body, the sintered magnetic body having the composition RTMB(R represents a rare earth element, Trepresents Fe or Co, M represents Al or the like, B represents boron, and a, b, c and d represent atomic percentages while 12≤a≤20, 0≤c≤10 and 4.0≤d≤7.0 are satisfied and b represents the balance), and the powder mixture containing an Roxide (Rrepresents a rare earth element) and alloy powder having the composition MM(Mand Meach represents Al or the like, and d and e represent atomic percentages while 0.1≤e≤99.9 is satisfied and d represents the balance) and containing 70 vol. % or more of an intermetallic compound phase. Accordingly, one or two or more elements selected from among R, Mand Mare caused to be diffused to grain boundaries in the interior of the sintered magnetic body or near grain boundaries within the sintered magnetic body primary phase grains.