PURPOSE: To attain acoustic reproduction with high fidelity and high reliability by providing a couple of drive coils to a diaphragm member so as to supply from a common power supply via 1st and 2nd switching elements provided individually on each drive coil.

CONSTITUTION: A couple of drive coils 27a, 27b are wound onto, e.g., a bobbin 25 with the diaphragm member 22 fitted thereto. The 1st switching element 44 is connected in series with one drive coil 27a and the 2nd switching element 47 is connected in series with the other drive coil 27b, both the drive coils 27a, 27b have the same electric characteristic and a power supply 48 is connected in common to both the drive coils 27a, 27b. When an inputted electric signal has one polarity, the 1st switching element 44 applies the switching and when the signal has the other polarity, the 2nd switching element 42 applies the switching. Thus, damage to the switching elements 44, 47 is prevented, the reliability is improved, and the increase in the distortion factor is suppressed to attain acoustic reproduction with high reliability.