PURPOSE: To mass-produce core block excellent in size precision and electric and magnetic characteristics by stacking and bodnign a thin-film amorphous magnetic matierial of fixed length coated with an adhesive, by carrying out a conductor process of its flank and then by working it in a desired shape by electropolishing.

CONSTITUTION: Amorphous magnetic material 10, led out by rolls 14, is thermally processed by 11 and coated with an adhesive in tank 12 and after an excessive adhesive is removed by doctor blade 13, it is cut by cutter 15 into pieces of fixed length, which are arranged in case 16 to obtain lamination ribbon 17. After lamination ribbon 17 is heated and applied with pressure into lamination block 20, a conductor process of flanks 20a and 20c of block 20 is performed and grindstone 22 with adrasive grains 22a protrucing on its surface is closely arranged on the worked surface of block 20 at an interval of approximate 20W80μ; while electrolyte 21 is continuously flowed between the both, the conduction-processed surface of block 20 is electropolished with the conduction-processed surface connected to a plus pole and grindstone 22 to a minus pole to work block 20 in a desired shape, thereby forming a core block.