Abstract: The present invention relates to a resin guardrail including a post, a plurality of guard plates coupled to the post, and connection members for connecting the guard plates to one another. Each of the guard plates of the guardrail is manufactured through extrusion. The guard plate comprises a hollow base body that takes the shape of a wave in cross section to include a rear ridge protruding rearward and having a flat portion and a front ridge protruding forward. The flat portion of the rear ridge and the front ridge are formed with first and second fastening holes, respectively, and the base body has solid portions for reinforcing regions with the first and second fastening holes formed therein.