1. A supervisory system for at least one elevator comprising: statistical means for generating statistical data of traffic conditions of the elevator over a predetermined period according to at least one threshold value; means for executing a learning function program for predicting traffic values on the basis of at least one adjustment value and the statistical data from the statistical means and for controlling the elevator in accordance with the predicted traffic value; information input means for supplying revision information; and revision means for revising the threshold value and the adjustment value in accordance with the revision information supplied by the information input means, thereby revising the generation of statistical data and the prediction of traffic values.