PURPOSE: To polish a work body in a highly accurate manner by forming metastable austenitic stainless steel into a fine line form by way of cold drawing and cutting into pieces, and having then charged into a vessel, where a variable magnetic field is produced, together with the work body.

CONSTITUTION: A work body S and an abradant 30 consisting of a magnetic substance both are charged in a vessel 20, having a variable magnetic field produced in this vessel 20, and thereby this abradant 30 is made to flow inside, whereby this work body S is polished. This case uses the abradant 30 in a cut-wire form induced and formed with a martensite structure by means of cold drawing operation of metastable austenitic stainless steel. At this time, the ratio of diameter : length of the abradant should be set to 1.2-20. A rate of formation in this induced martensite structure is within the range of about 20-50%, and since magnetic susceptibility is small, the abradant 30 comes to freedom even in a magnetic field, thus it is flowable randomly in the variable magnetic field.