A swing control system for a hybrid construction machine includes a swing operation lever, a hydraulic pump, an electric swing motor that makes an upper swing structure swing against a lower driving structure in accordance with an electric control signal corresponding to an operation amount of the swing operation lever, a swing parking brake released in accordance with an operation signal of the swing operation lever to drive the swing motor, a control valve which drives a hydraulic cylinder for the swing parking brake by hydraulic fluid from the hydraulic pump to release the swing parking brake if the control valve is shifted by an input of the operation signal from the swing operation lever, and a controller that controls the swing parking brake through shifting of the control valve or controls driving of the swing motor in accordance with the operation signal from the swing operation lever.