A magnetic actuator, particularly for selection devices in hosiery knitting machines or the like, comprising a main magnet, which has at least two poles arranged side by side and separated by a discontinuity, and a selection electromagnet, which is provided with at least one pole arranged in alignment with the discontinuity and spaced laterally with respect to it. The damping device has a movable, electrically conductive component, which is at least indirectly connected with the creel and is arranged such that the movably seated component intersects the magnetic field of a stationarily arranged magnet system, preferably a permanent magnet system, in a contactless manner. 90 times the inner diameter of a trunk of the outer tube.