PURPOSE: To obtain a magnet, which has a high rustproof effect and a good economical efficiency, by a method wherein a corrosion-resistant resin layer having a specified value of the coefficient of water absorption is applied on the surface of a permanent magnet, which is formed of necessary basic components and has the content of oxygen of a specified value and a void content of a specified value, in a prescribed thickness.

CONSTITUTION: A corrosion-resistant resin layer whose coefficient of water absorption is of 5% or lower is applied on the surface of a permanent magnet, which contains at least one kind of rare earth elements including Y, at least one kind of transition metal elements and at least one kind of group IIIb elements as its basic components and has the content of oxygen of a weight ratio of 1500ppm or lower and a void content of 2% or lower, in a thickness of 1 to 80μm. Whereupon, the magnet becomes a permanent magnet, whose rustproof effect is increased, whose economical efficiency is good and which has a magnetic anisotropy.