The present invention may provide a accurate drive unit 1 which comprises an electromechanical transducer 10, a drive element 12 fixed on the one end of the electromechanical transducer 10, a movable element 11 engaging with the drive element 12 frictionally and a drive circuit 3 applying a cyclic drive voltage to the electromechanical transducer 10, in which the oscillation of the drive element 12 as the result of the expansion and contraction of the electromechanical transducer 10 due to the drive voltage causes relative displacement of the movable element 11 to the drive element 12. The waveform of drive voltage is varied according to the relative position of the movable element 11 to the drive element 12.