A method for producing an RE-containing alloy represented by formula R(T1−xAx)13−y (wherein R represents Ce, etc.; T represents Fe, etc.; and A represents Al, etc; 0.05≦x≦0.2; and −1≦y≦1) including a melting step of melting alloy raw materials at 1,200 to 1,800° C.; and a solidification step of rapidly quenching the molten metal produced through the above step, to thereby form the first RE-containing alloy, wherein the solidification step is performed at a cooling rate of 102 to 104° C./second, as measured at least within a range of the temperature of the molten metal to 900° C.; and an RE-containing alloy, which is represented by a compositional formula of RrTtAa (wherein R and A represent the same meaning as above, T represents Fe, etc.; 5.0 at. %≦r≦6.8 at. %, 73.8 at. %≦t≦88.7 at. %, and 4.6 at. %≦a≦19.4 at. %) and has an alloy microstructure containing an NaZn13-type crystal structure in an amount of at least 85 mass % and α-Fe in an amount of 5-15 mass % inclusive.