Permanent magnet on R-T-B base

An object of the present invention is to provide an R-T-B based permanent magnet showing high residual magnetic flux density Br and coercive force HcJ, and further showing the same also after heavy rare earth element is diffused along grain boundaries. Provided is an R-T-B based permanent magnet in which, R is a rare earth element, T is an element other than the rare earth element, B, C, O or N, and B is boron. T at least includes Fe, Cu, Co and Ga, and a total of R content is 28.0 to 30.2 mass %, Cu content is 0.04 to 0.50 mass %, Co content is 0.5 to 3.0 mass %, Ga content is 0.08 to 0.30 mass %, and B content is 0.85 to 0.95 mass %, relative to 100 mass % of a total mass of R, T and B.