To provide a swivelling drive controller capable of swivelling smoothly without causing the overshoot of the speed of swivelling in a construction machine for swivelling and driving an upper structure by an electric motor.

This swivelling drive controller for driving and controlling a swivelling mechanism of the construction machine swivelled and driven by the electric motor includes a feedback control part 52 for generating a torque command value for changing the speed of swivelling by a control system including at least a proportional component and an integration component based on deviation between a speed command value and the speed of swivelling. The feedback control part 52 does not employ the integration component at the generation of the torque command value when it is detected that an amount of the operation of a lever 26A moves into a region where it exceeds a predetermined value (for example, an amount of operation corresponding to 10% of the maximum value of the speed command value) in a counterclockwise (clockwise) direction swivelling drive region from a zero speed command region.

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