In a feed drive apparatus wherein a moving element 27 is driven by drive legs 21, 22 having extension/contraction deforming parts 23 and shear deforming parts 24, sine wave drive voltages are respectively applied to the extension/contraction deforming parts 23 and shear deforming parts 24 of the drive legs 21, 22 in order to permit high speed operation, and make the average voltage effectively zero.