Electromechanical parking brake

There is provided an electromechanical actuator for a parking brake system of a vehicle including an electric motor (6); bi-directional transmission means (10) associated with the rotor of the motor for transmitting motion from the rotor to a force application unit (16), as well as from the force application (16) unit to the rotor. The force application unit (16) is at least indirectly connected to the brake system, and locking and unlocking means (8) which, in a first state, allows the force application unit (16) to freely move and, in a second state, prevents the force application unit (16) from moving at least in one direction.