PURPOSE: To attain good working performance and to assemble accurately a tweeter by providing a case for speaker unit guide to the inside of cavity of a woofer magnetic circuit.

CONSTITUTION: The tweeter is assembled through the inside of an exterior magnetic circuit of the woofer from the woofer back side. Since the tweeter is assembled along a tweeter guide case 7b in this case, a problem of the tweeter attracted in any direction is avoided even if magnetic force is applied to the tweeter magnetic circuit by the woofer magnetic circuit. Thus, the working performance at the tweeter assembling is improved. Further, the tweeter guide case 7b is assembled in the cavity of a woofer B plate 14b and the tweeter is fixed to the center of the case 7b, allowing to position easily the tweeter at the center of the woofer magnetic circuit.