Rotary cutting head of threads for brushcutters, lawnmowers, trimmers, hedge trimmers or the like, said head comprising, on the one hand, a hub (18, 19) that extends centrally and axially in the latter and to receive a drive shaft (20 ) in order to allow, by means of joining and transmission of the driving torque (21, 22), the rotating drive of said head around its axis of rotation (X) and axial locking means (23, 24, 28 ) of the head in the drive shaft (20) and, on the other hand, a housing (1) housing a support body (2) comprising a locking system (3, 3 ', 4, 4', 12) of At least two short or long cutting or shear threads (5, 5 ') and, if necessary, a winding shaft (6) preferably integral with the support body (2), which allows, if appropriate, the winding of each long wire (5, 5 ') in said head further comprising connection means (7, 8) between the housing (1) and the body sop orte (2), and whose aforementioned hub (18, 19) is integral with the housing (1) and / or the support body (2) and said housing comprising at least two holes (9, 9 ') for the passage said threads through the latter, where the locking system (3, 3 ', 4, 4', 12), comprises, on the one hand, at least two mobile, mutually independent locking elements (3, 3 ') , and each associated with a clamping surface (4, 4 ') integrated in the support body (2) and comprising a clamping face (10, 10') and a supporting face (11, 11 ') and, characterized in that on the other hand, a single elastic organ (12) capable of exerting and applying a pressure on the support face (11, 11 ') of each blocking element (3, 3') that allows to hold and block each thread ( 5, 5 ') between the clamping face (10, 10') of the blocking element (3, 3 ') in question and the associated clamping surface (4, 4') and why, eventually, the supporting body ( 2) and the housing (1) are adapted to be mounted mutually and rotatably in order to allow, if necessary, the winding of each long thread (5, 5 '), in the clamping and locking state, ar
