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