Abstract: The helmet comprises a crown (1) with belts (2) which are blocked from moving with respect to the crown by means of buckles (3). The belts are wound on the buckles. The buckles are inserted in slits (6) formed on the crown (1) along its entire thickness. Recesses (7) are formed on the external surface of the crown. The buckles (3) fit into the recesses so that the external surface of the buckles is essentially on the level of the external surface of the crown (1).