An electromagnetic actuator, particularly for needle selection devices in machines for knitting, hosiery or the like, with high gauge. The electromagnetic actuator comprises a main magnet which has at least two polar regions which are side-by-side and separated by a gap and two selection electromagnets, each provided with at least one polar region which is aligned with the gap and spaced laterally from said gap. The at least one polar region of a selection electromagnet is arranged laterally on the side opposite to the at least one polar region of the other selection electromagnet with respect to the gap. The selection electromagnets can be activated individually to generate or cancel or reduce an attractive magnetic force at the corresponding polar region.