A mowing device for the treatment of vegetation, adapted to be coupled to a carrier and to be connected to a drive unit, where said mowing device includes an armature (22), in which spindles (7a, 7b are mounted) ) mowing, which are provided on one side of mowing blades and on the opposite side of distribution elements for connection with transmission elements, in which in the armature (22) a transmission mechanism is further located to drive the mowing spindles (7a, 7b), and in which - the mowing spindles (7a, 7b) are arranged in two rows parallel to each other, defined by longitudinal lines (8, 9), located at a distance (L) of separation between them, - the mowing spindles (7a, 7b) of each row are interconnected by means of the transmission elements, - the centers of the mowing spindles (7a) of the first row in a line (8) are located so that (P) is the separation among them, - the centers of the mowing spindles (7b) of the second row in the line (9) are located such that (P) is the separation between them, - the centers of the mowing spindles (7b) of the second row are displaced in the direction of the lines (8, 9) in a distance (P / 2), equal to half the spacing (P), in relation to the centers of the spindles (7a) of mowing the first row in line (8), - the line that connects the center of each mowing spindle (7a) in the first row in line (8) with the center of the mowing spindle (7b) immediately adjacent to the second row on the line (9) forms an angle (αacute with the two parallel longitudinal lines (8, 9) for which the following equation is fulfilled: ** Formula ** - the value of the angle (α) is in the range between 15º and 60º, characterized in that - the transmission mechanism for operating the mowing spindles (7a, 7b) comprises two mont transmission devices attached in parallel in the frame (22) and connected to each other, - the first transmission device is arranged for rotation in a direction of rotation, and is connected through transmission elements with
