Rtb-based alloy and method of manufacturing a magnet material by

One kind of R-T-B based magnet material alloy, the alloy comprising, as a main phase, R2T14B phase and R is concentrated in the R-rich phase, a main phase having a major axis and dendritic branching out from the main secondary dendrite dendrite arms, by generating a region having a volume ratio of the secondary dendrite arm 2 to 60%, even in the case of reducing the addition amount of the heavy rare, it is possible to secure excellent in the R-T-B based sintered magnet coercive force. R-rich phase spacing is preferably 3.0μm or less, the volume ratio of chilled crystal is preferably 1% or less. Further, the secondary dendrite arm spacing is preferably 0.5 ~ 2.0μm, the R-rich phase is shorter than the ellipse is preferably 0.5 or less.