Abstract: Apparatus for controlling both collective and cyclic pitch of blades of a helicopter rotor comprises a non-rotating plate which is connected via a fixed caliper and servo controls to a fixed housing and to which is attached the internal ring of a ball race bearing. The external ring of the bearing carries a rotating plate, which is connected by means of rotating caliper or links to each of the rotors and by means of pitch rods to control levers for adjusting the pitch of the blades. The non-rotating plate is fixed to external armatures of laminated joint pieces which are mounted slidingly up and down a guide base. The collective pitch is controlled by sliding the assembly of non-rotating plate and joint pieces up or down the guide base while the cyclic pitch is controlled by inclining the assembly relative to the main rotor shaft. This inclination involves deformations in the laminated joints.