PURPOSE: To suppress radio frequency noise by generating individually two kinds of voltage signals symmetrical with respect to a potential of a prescribed point based on the same drive signal and correcting the potential of the prescribed point through the result of detection of a current signal so as to improve the current symmetry.

CONSTITUTION: A complementary signal generating block 10 receives a drive signal and generates complementary (symmetrical) voltage signals. In this case, a symmetrical point voltage fed back from a current correction feedback block 12 is used for a reference voltage. A drive means (not shown) receives a voltage signal to drive a + bus and a - bus. Resistors R1, R2 are current direction resistors to detect a current outputted the + bus and the - bus and the voltage across the resistors is detected by the current correction feedback block 12. The current correction feedback block 12 applies feedback control to the symmetrical point voltage based on the result of detection to ensure the current symmetry.