a device for locking a root of a rotor blade in a groove in a rotor disk of a turbomachine including : a circular ring sector configured to be mounted , transversely to the axis of the turbomachine , in a groove in the rotor disk ; at least one locking wedge , which is rigidly secured and perpendicular to the ring sector , and extends parallel to the axis of the ring sector so as to hold the root of the blade radially in the groove ; and at least one locking tooth extending from the ring sector radially with respect to the axis of the ring sector , so as to prevent the root of the blade from moving axially in the groove .