A tube cut-off unit is arranged at the downstream end of a tube mill and is powered by a drive unit mechanically driven by the main shaft of the mill which drives the tube forming rolls. The drive unit mechanically rotates a crank which, through a link, reciprocates a slide along the path of travel of the tube. A tube cut-off blade on the slide is cam actuated to sever the tube. Means are provided to insure that the slide is moving at a constant speed and at the same speed as the tube when the tube is being severed.