An improved Cotton knitting machine, in which the needle bar (1) is actuated by a lever system which comprises an arm (4) which is fixed to the needle bar and is articulately connected to a first lever (5) provided with recesses (7,8) for engagement to a pivot (9) which is fixed on a second lever (11) which is radial with respect to a horizontal supporting shaft (12) and is controlled by an actuation cam (15) by way of a roller (14) which is urged onto the profile of the cam (15) by elastic elements (17), wherein the pivot (9) can be arranged on the second lever (11) so as to produce an oscillation of the arm (4), by action of the first lever (5), according to a preset criterion.