PURPOSE: To obtain the surface-treated permanent magnet, having excellent tight adhesiveness with a permanent magnet body, an excellent corrosion-resistance for a long time, and excellent reliability, at a low cost by a method wherein a chromate film and a resin film are laminated on the surface of a rare earth-iron boron permanent magnet body.

CONSTITUTION: A chromate film and a resin film are laminated on the surface of a rare earth-iron-boron permanent magnet body. Also, said rare earth-iron-boron permanent magnet body is chemically formed using a chromic acid aqueous solution, then resin is coated thereon, and a permanent magnet having excellent corrosion resisting property can be manufactured. The above-mentioned chemical formation is conducted using a chromic acid aqueous solution having the optimum chromic acid concentration of 1W50g/l (4W9g/l), the content of alkaline metal in the chromate film is controlled to bring it to 1000ppm (weight ratio), and it is suitable to perform a blast treatment using Al2O3 grains before the chemical formation is conducted. Also, it is suitable to form the above-mentioned resin film using a kind selected from furan resin and epoxy resin, or using a combination film made of two or more kinds of the resins such as above-mentioned one.