PURPOSE: To reduce the height of a magnetic circuit and to make the whole part of the speaker compact by using a center pole or yoke composing a 2nd magnetic circuit also for a shield cover.

CONSTITUTION: A magnetic-proof shield cover 9 is used for the lower plate comprising the 2nd magnetic circuit 26. It is also used for a center pole member 9A. After a 1st magnetic circuit 25 having a cylinder part 6A is assembled on a yoke 6, a gap gage is engaged with the center pole member 9A which is integrally formed by the shield cover 9 as a 2nd magnetic circuit 26. The gap gage is inserted into the inner diameter of the cylinder part 6A of the 1st magnetic circuit 25 to integrally form the 1st and the 2nd magnetic circuits 25 and 26. By only assembling the 1st and the 2nd gaps 10 and 11, the speaker assembling method not requiring the shield cover assembly process can be obtained.