A group-supervising control system for an elevator includes a cage position prediction unit for predicting cage positions after a predetermined time period based on the present positions, a service available time period distribution calculation unit for calculating the time periods until the service is available (predicted arrival times of a cage capable of responding to a hall call earliest) based on the predicted cage positions, and an assignment correction value calculation unit for calculating assignment correction values for correcting assignment estimation values based on the distributions of the time periods until the service is available. Unevenness in the time periods until the service is available with regard to the respective floors is decreased.