An elevator group control apparatus performs operation control of a plurality of elevators by detecting a downward traffic flow ratio of traffic flows departing downward from floors higher than a prescribed main floor in the total traffic flow departing from one floor to another. If the downward traffic flow ratio is not less than a prescribed reference value, a standby mode for downward traffic flow is made effective, in which at least one elevator car is caused to be on standby on a floor higher than the main floor and at least one elevator car is caused to be on standby on the main floor.