The invention relates to an inertial sensor based on the magnetic levitation of an inertial mass comprising an active magnetic bearing unit arranged in such a way as to levitate the inertial mass and characterized by the fact that it furthermore comprises additional active magnetic bearings units arranged in such a way as :- to control the position of said inertial mass along three independent axis. - to create, for any of said independent axis, restoring forces that can be oriented in any of the two directions of said independent axis.