A continuously fed tube is momentarily halted at a cutting station and quickly cut by a rotating knife. The tube is continuously advanced from driving rollers to idler rollers and passes through intermediate pinch rollers which are cam controlled in synchronism with the cutting process to bow the tube at a rate which causes the tube portion at the cutting station to briefly stop during cutting. The cutter includes a planetary gear set having a carrier rotatable about a central axis which carries a knife for rotation about another axis while it revolves about the central axis. The knife makes many rotations per carrier revolution but is in position to cut the tube during one of the rotations.