PURPOSE: To enable the manufacture method of a permanent magnet to omit its adhesively attaching process, by forming mounting shafts, mounting a diaphragm, in both end parts while insertion molding the permanent magnets in an intermediate part, in a movable member made by synthetic resin.

CONSTITUTION: The method integrally forms mounting shafts 7, mounting a diaphragm, with movable members 6 in both end parts while insertion molds permanent magnets 3 in an intermediate part, in the synthetic resin made movable members 6. By this manufacture method, molding of the permanent magnets 3 and the mounting shafts 7 for the synthetic resin made movable members 6 eliminates the necessity for an adhesively attaching process of the permanent magnets 3 and for screwing work of the mounting shafts 7 while also a tilt o the mounting shafts 7.