SIDE SILL FOR MOUNTING SLIDING DOOR OF VEHICLE

A side sill for mounting a sliding door of a vehicle may support operations of opening and closing the sliding door without reducing an area of a space inside the vehicle. The side sill includes an inner panel that extends in forward and rearward directions and which is mounted at a side portion of a floor panel of a vehicle body, and an outer panel formed integrally with an upper end and a lower end of the inner panel so as to be disposed opposite the floor panel of the vehicle body based on the inner panel, the outer panel having a module mounting part for mounting a sliding module for the sliding door based on upward and downward directions, the module mounting part being open towards an outside of the vehicle body.