Method for producing R-T-B system sintered magnet

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A sintered R-T-B based magnet work contains R : 27.5 to 35.0 mass % (R is at least one rare-earth element which always includes Nd), B : 0.80 to 0.99 mass %, Ga : 0 to 0.8 mass %, M : 0 to 2 mass % (M is at least one of Cu, Al, Nb and Zr), and a balance T (T is at least one transition metal element which always includes Fe, with 10% or less of Fe replaceable by Co). [T]/55.85>14[B]/10.8 is satisfied where [T] is the T content (mass %) and [B] is the B content (mass %). At least a portion of a Pr—Ga alloy is in contact with a portion of the sintered magnet work surface, and a first heat treatment is performed at a temperature between 600° C. and 950° C. A second heat treatment is performed at a temperature lower than the temperature of the first heat treatment and between 450° C. and 750° C.