PURPOSE: To improve reproducing characteristic by using a sheet of paper for a skin member adhered to both faces of a core member, changing the hardness of the skin used for the front side and the skin used for the rear side relatively and controlling internal loss and rigidity so as to decrease a peak due to split resonance generated at a high frequency and the film resonance of the skin.

CONSTITUTION: The skin member 2 at the rear side and the skin member 3 of the front side are formed by manufacturing to sheets a pulp member and pressing it. Further, the skin members 2 and 3 are formed with different pressure at the pressing in the process of forming. That is, the skin members 2 and 3 constitute a honey-comb diaphragm with different hardness. In vibrating the honey- comb diaphragm while assembling a voice coil at an inner circumferential part, the skin member 4 or 3 formed softly with a small pressing pressure has a proper internal loss, and the skin member 3 or 2 formed with a large pressing pressure to be hard keeps a proper rigidity so as to suppress a peak due to the split resonance of a high frequency band thereby keeping the high frequency reproducing limit band.