PURPOSE: To raise an assembling accuracy so that a radiation surface of a sound wave becomes flat, by inserting a pole piece into a round hole which has been provided in the center of a lower plate, from the bottom of a magnetic circuit, and fixing the pole piece and the lower plate, in a dynamic loudspeaker.

CONSTITUTION: A frame 11 is installed to a magnetic circuit assembly consisting of a lower plate 1, a magnet 3 and an upper plate 4, and an assembling jig 13, and a voice coil bobbin assembly consisting of a voice coil 7 and a bobbin 6 are inserted. Subsequently, a damper 5 is inserted into a prescribed position, and the bobbin 6 and the damper 5 are made to adhere. Moreover, a diaphram to which an edge 10 has been made to adhere in advance is inserted into the bobbin 6, and the diaphragm 8 and the bobbin 6, and the edge 10 and the frame 11 are made to adhere, respectively. After an adhesive agent of each part has been hardened, the assembling jig 13 is drawn out from the plate 1, a pole piece 2 is inserted from the rear of the plate 1, and each of them is fixed with a screw. In this way, the respective component parts can be assembled in order at a prescribed position.