Portions excluding magnetic elements of a laminate film of magnetic films or the like constituting magnetic elements (1) are oxidized/nitrided or oxynitrided to be insulated by a plasma processing using a conductive mask (17), whereby a plurality of magnetic elements are separated. This laminate film comprises a magnetic element region (18) formed with magnetic elements (1) and an insulated region (19) consisting of oxides/nitrides or oxynitrides. Upper wiring such as a bit line (3) is formed later. Since the conductive mask used in forming the insulated region is made part of the upper wiring, the magnetic elements and the upper wiring can be disposed in contact with each other.