A mowing head is described, particularly for a bush-cutter, comprising a rotor rotating around a rotation axis (R-R) and its cover, in which the rotor is equipped with at least one supporting surface from which at least one external perimeter wall and at least one internal wall depart, such external perimeter wall and such internal wall mutually defining at least one housing seat of at least one length of flexible cutter, the external perimeter wall being radially equipped with at least one slit adapted to allow at least one length of the flexible cutter to go out from inside the housing seat to the outside.