Optimal feedforward trajectories of a trolley are derived in an overhead travelling crane for quick suppression of residual oscillation in a hoisting load by using vibration manipulation function. Since residual vibration of a linear oscillator can be suppressed or emerged by moving the base along the function, the same effect can be acquired by deciding intermittent acceleration of the trolley. By deciding the route of the load as that of linear oscillation, proper trajectory can be determined under the influence of nonlinearity and the elevation/descendent of the load.