To prevent adhesion of weld slag, clinging to a squeeze roll, to an electric resistance welded pipe.

A cleaning member 37 of a wiper 33 is pressed on a concave curve 28 and an upper flange 30 of a squeeze roll 8, and weld slag s is cleaned off by the rotation of the squeeze roll 8. The wiper 33 firmly fixes the cleaning member 37 to a board 36 connected to a shaft 34 via a rotatable arm 35. The cleaning member is composed of flannel. A locking member 39 is installed to the board 36 which fixes the cleaning member 37. The locking members 39, 39 of a pair of the squeeze rolls 8, 8 are connected pulling each other with a coil spring 40 and the cleaning members 37, 37 are pressed against the concave curves 28, 28. A cooling pipe 42 is installed to spray cooling water to the squeeze roll 8 to rearward of the rotating direction of the squeeze roll 8.