A guardrail for roads is provided to avoid brittle fracture in case of car crash and induce ductile fracture instead, so as to prevent the car from passing through the guardrail by filling and hardening concrete within a steel pipe. In a guardrail for roads for coupling and fixing a guardrail(130) on the upper side of a support(150) standing on a ground surface(140), a concrete(120) is filled and hardened within a hollow steel pipe(110) of a predetermined length. A lower part of the metallic support is buried in the ground, and a guardrail insertion hole(160) is formed on the upper side of the metallic support. One end of the guardrail is tightly fitted into the guardrail insertion hole.
