PROBLEM TO BE SOLVED: To provide a ridge plastering machine capable of cutting through the top portion of an old ridge with a constant depth regardless of the surface conditions of the top portion.SOLUTION: There is provided a ridge plastering machine installed on a traveling body, installed at the position offset sideward of the traveling machine body, and comprising a top portion treating rotors 32 provided with plural tilling claws 32b on a rotation shaft 32a rotatably supported for cutting through the top portion of the old ridge K and performing the ridge plastering accompanied with the advance travel of the traveling machine body. The top portion treating rotor 32 is supported as vertically freely movable to the top portion Kt of the old ridge K. A grounding member 60 grounding to the top portion Kt is disposed forward of the travelling direction of the top portion treating rotors 32 within the cutting range H where the top portion Kt is cut through by the top portion treating rotors 32.
