PURPOSE: To provide a grease-lubricated rail guide which can avoid grease from leaking and adjust gaps using a shim.

CONSTITUTION: In the rail guide of a container spreader, in which a pair of right and left reach rails 2 is freely expandably mounted on a cylindrical rail holder 1 and a sliding pad 4 fitted into the pad mounting hole 5 of the rail holder 1 is pressed and held in place by a cap 6 bolted to the outer surface of the rail holder 1, a shim 8 is interposed between the rail holder 1 and the cap 6 so that the gap between the end face of the sliding pad 4 and the side of each of the reach rails 2 can be adjusted. The sliding pad 4 is provided with a lubricating hole 9 to introduce grease into the gap, and the cap 6 is provided with a cylindrical plug 11 to be tightly fitted into the lubricating hole 9, and a nipple 12 for supplying grease is attached to the plug 11.