Structure for Preventing Sliding Door From Swaying

A structure for preventing a sliding door from swaying includes a rail mounted in a first direction that is a longitudinal direction of a vehicle body, a rail roller unit rollably connected to the rail, a sliding module configured to apply driving power in the first direction to the rail roller unit through a cable, a slider mounted on the rail roller unit, a movement support unit configured to support the sliding door, wherein a first side of the movement support unit is fixed to the sliding door, and a second side of the movement support unit is rollably connected to the slider, and a spindle assembly configured to operate a spindle between the sliding door and the rail to move the sliding door in a second direction perpendicular to the first direction.