A feed apparatus for tubing in which a pair of arms are mounted in scissors fashion and a feed roller and drivingly connected pulley are mounted at each free end of each arm. An endless drive belt is trained around the pulleys and a motor drivingly engages the belt so as to drive the pulleys and thereby the feed rollers. As the arms move in scissors fashion to move the feed rollers into and out of driving engagement with the tubing, the length of the path of the drive belt is shortened but a belt tensioning mechanism operates to compensatingly increase the length of the belt path to maintain a constant tension on the belt and thereby a constant drive to the feed rollers. The tensioning mechanism includes an air cylinder and a tensioning roller secured to the free end of the pistion rod of the air cylinder. A constant air pressure is maintained in the air cylinder so that the tensioning roller is automatically moved outwardly or inwardly to maintain a constant tension on the drive belt as the feed rollers move toward or away from the tubing.