The present invention relates to an electromagnetic contactor including a stationary armature which includes a housing enclosure for a coil for generating a magnetic field, the enclosure having an opening, a closing cover for the opening of the enclosure, the closing cover having an aperture, and a movable armature passing through the aperture of the closing cover for the opening of the enclosure, further including a guide ring made from non-magnetic material which is arranged in the aperture of the closing cover so as to have, between a first wall in contact with the wall of the aperture of the cover and a second wall facing towards the movable armature, a thickness corresponding to the minimal radial gap between the movable armature and the stationary armature.