PURPOSE: To miniaturize the whole of device, shorten the time required for cutting a work and reduce a load applied on a cutting edge in cutting of the work.

CONSTITUTION: A spindle 108 is supported rotationally in a chuck head of a work chuck device 7. Plural chuck bodies 109 are installed openably at the tip of the spindle 108. The chuck bodies 109 are closed and the end part of a pipe material W is chucked by means of the chuck bodies 109. A machining head 136 is elevatably supported in a column 12 of a work cutting device 9, and a disk cutting rotary edge 137 is installed at the tip of the spindle of the machining head 136. While rotating the cutting rotary edge 137 by means of a motor 139 for a rotary edge, the machining head 136 is lowered by means of a head elevating/lowering cylinder 138, and the pipe material W is cut into the preset length. In this process, the chuck bodies 109 are rotated via the spindle 108 by means of the motor, and the rotation is applied to the pipe material W.