A group supervisory control device for an elevator, by which elevator control devices for controlling a plurality of cars are controlled as one group, comprising: hall call assignment means by which a specific car is assigned to a hall call registered by hall call registration means for registering a hall call at each floor; operation prediction means by which, when the specific car has stopped at a responding hall, it is predicted which is the operation to the next hall registered by the hall call registration means according to the car traveling direction and the car load, regenerative operation which regenerates power or power running operation which consumes power, and the time for which the regenerating operation or the power running operation is performed is predicted; and door open time control means by which the time for which the regenerative operation or the power running operation of the specific car is performed, which is predicted by the operation prediction means, is compared with the remaining running time of any other car performing the power running operation, when the regenerative operation of the specific car is performed, or with the remaining running time of any other car performing the regenerative operation, when the power running operation of the specific car is performed, as already predicted by the operation prediction means, overlap time for which the specific car and the any other car perform the regenerative operation and the power running operation simultaneously is calculated, and door open time set for the specific car, which is used for the calculation, is changed and the overlap time is calculated to determine the door open time which can obtain longer overlap time, whereby a door is closed. hall call assignment means by which a specific car is assigned to a hall call registered by hall call registration means for registering a hall call at each floor; operation prediction means by which, when the specific car has stopped at a responding hall, it is predicted which is the operation to the next hall registered by the hall call registration means according to the car traveling direction and the car load, regenerative operation which regenerates power or power running operation which consumes power, and the time for which the regenerating operation or the power running operation is performed is predicted; and door open time control means by which the time for which the regenerative operation or the power running operation of the specific car is performed, which is predicted by the operation prediction means, is compared with the remaining running time of any other car performing the power running operation, when the regenerative operation of the specific car is performed, or with the remaining running time of any other car performing the regenerative operation, when the power running operation of the specific car is performed, as already predicted by the operation prediction means, overlap time for which the specific car and the any other car perform the regenerative operation and the power running operation simultaneously is calculated, and door open time set for the specific car, which is used for the calculation, is changed and the overlap time is calculated to determine the door open time which can obtain longer overlap time, whereby a door is closed.