Abstract: This invention, being an improvement on the kind of fixed road railing adopted widely now, provides a new system of replaceable road railing comprising mainly of an underground sleeve, into which a pillar is inserted, a pillar with blades at its bottom, and a device inside the pillar which, by means of its upward and downward movement, controls the expanding and contracting movement of the blades of the pillar and, as a result, causes the blades to tighten against or loosen from the inner surface of the sleeve and, thus the pillar can be easily inserted into the sleeve or taken out from it thereby.