transferring cam 53 and a lowering cam 52 which are retracted the auxiliary jacks 26 are then pushed downwardly by a next lowering cam 56 into a starting position the selector jack that has been advanced by the middle lifting portion 63 is immediately lowered by the lowering portion 64 such selector jacks and the selector jacks pushed to a retracted position out of the camming action are again aligned by the arranging cam 71 in the system b the selector jacks associated with needles for knitting in a following step are selected again by the selectors 70 the butts 33 of the selected selector jacks which are not pushed by the selectors again ride on the rear lifting portion 63 in the system b pushing the auxiliary jacks 26 upwardly into a position subject to the camming action by the knitting cam 55 preparation is thus completed at this time the selected main jacks are positioned in a location subject to the camming action by the tuck cam 48 and the auxiliary jacks selected separately from the auxiliary jacks which have raised the main jacks into the position subject to the camming action by the tuck cam are located in a position subject to the camming action by the knitting cams 55 in fig6 the knitting cams 49 in the zone d are in its retracting position and in the zone e the knitting cams 55 and the lowering cam which is located rear in the direction of travel of the carriage in each system a b are in their projecting position when the carriage makes a.