PURPOSE: To make it feasible to automatically and continuously mark and cut medium bore tubes of various diameters.

CONSTITUTION: The movable frame 4 of a grasping mechanism 7 is guided in a freely reciprocating motion on the conveyor body 1 of a roller conveyor 3. The stamping end part of the a marking press 8 is guided so as to be driven along the right angle bisector formed by the upper surface of the roller conveyor 3 and a gasping reference body. A bore tube marking device is comprised of a cutter 10 which has its cutting unit 9 arranged in a freely reciprocating motion on the upper part of the roller conveyor 3 at the reciprocating motion terminating position of the grasping mechanism 7 and near the marking press on the upper stream side in the transfer direction of the marking press 8.