To efficiently cutting work a flange end face by concentrically cutting a flange end surface while a tool rest is slid in a radius direction with rotating together with a spindle tube, and the flange end face of a large-diameter pipe is supported in parallel.

When a change valve 72 is operated to send high-pressure oil to the head side oil chamber 74 of a hydraulic cylinder 62 with a spindle tube rotated, the high-pressure oil in a rod side oil chamber 76 is returned to an outside oil pressure source via the change valve 72 to proceed a piston rod 66. Then a scroll board is rotated together with a collar-attached nut 70 to slide a tool rest in a radius direction to cutting work a pipe end surface by a cutting tool. When a piston progresses to the front end, the change valve 72 is operated to send the high-pressure oil to the rod side oil chamber 76 of the cylinder 62; and when the high-pressure oil in a head side oil chamber 74 is returned to the oil pressure source via the change valve 72, the piston rod 66 is retreated to cutting work the pipe end surface.