The invention provides a curling device for double-rib cylindrical flexible freight bags. The curling device comprises a cylinder-driven curling device, a spot welder probe, a motor flanging device and a manual length adjusting device, and a spot welder, automatic flanging and automatic spot welding are adopted in the curling device. The curling device is capable of achieving automatic flanging and automatic spot welding, so that full-automatic integration of flexible freight bag curling is realized; and the curling device is good in curling effect and high in finished product ratio and efficiency.