PURPOSE: To present sure prediction quickly and reduce the distrust feeling of a user due wrong prediction by detection that difference between the appraisal value of an optimum machine and the appraisal values of machines other than the optimum machine is less than a predetermined value, deterring the lighting of the prediction light of the optimum machine by this detection.

CONSTITUTION: Based on information from a car call controller 6 in an elevator car 5, information via a tail code 7, and information of a hall call controller 8 sent to an elevator control part 4 in an elevator control pannel 3 connected to an elevator LAN2, precast arrival time difference is computed by means of an evaluation computation part 9 and a precast arrival time computing part 10 in a group management control pannel 1. With the computation, it is possible to prevent generation of precast when evaluation values of the optimum car non-optimum cars with respect to hall calls are under a specified value. Generation of precast errors can be reduced accordingly.