Disclosed is a shock absorber for buffering the barrier wall of a road. According to the present invention, a horizontal inner pipe bumper is inserted into a pedestal attached to a boundary of a barrier wall and joined to the support pillar. The buffer rail transversely connected to the protruding portion of the buffer pad on the front surface of the pedestal constitutes the buffer portion of the collision portion barrier wall, and when the buffer pad adhered to the inner pipe bumper is displaced upright, tension of the elastic rail connecting the buffer pad and the elastic rail block is generated, and the guard rail of the pillar is coupled to the barrier bridging body by a connecting member.