To provide a magnetic polishing method and its device using a magnetic pin which can polish and processing harden the work surface by rotating magnetic particles easily following to the rotating magnetic pole, even in an even magnetic field with the same magnetic field.

In a magnetic polishing method to polish the inner surface of a work 4 by rotating the work 4 and the magnetic field relatively, as well as by providing magnetic abrasive particles 5 to the inner surface of the work 4 such as a pipe consisting of a non-magnetic body such as a ceramics and a stainless steel set in a magnetic field, magnetic particles with the form having a magnetic anisotropy (a magnetic pin tool with a specific diameter and a specific length) 6 are used adding to the magnetic abrasive particles 5. Even in a polishing process necessary to form an even magnetic field of the same magnetic field, the magnetic particles 5 and 6 are rotated easily following to the rotary magnetic field, without rotating together with the work 4, and the surface of the work 4 can be polishing processed in a super precision.