Contactor that can be actuated by a magnetic field, this contactor comprising at least one first and one second blades (12, 14) extending in a longitudinal direction: - the first blade comprising at least one contact block P 1i having a contact face F 1i, - the second blade comprising at least one contact block P 2i facing the contact block P 1i and having a contact face F 2i, the contact blocks P 1i and P 2i facing one another when the intersection of the face F 2i and of the projection in the transverse direction, at right angles to the longitudinal direction, of the face F 1i on the face F 2i forms an area of overlap whose surface S zi is strictly greater than zero, - at least one contact block of each pair of contact blocks P 1i, P 2i facing one another being able to be displaced in the transverse direction, under the effect of the magnetic field, between: • a closed position in which the faces F 1i and F 2i are directly in mechanical contact with one another to allow the passage of a current, and • an open position in which the faces F 1i and F 2i are separated from one another by an air gap to electrically insulate them from one another, - the first and second blades (12, 14) comprise contact blocks forming several pairs of contact blocks P 1i, P 2i facing one another, immediately consecutive in the longitudinal direction, and - each blade comprises at least one bridge Pt ji, each bridge directly mechanically linking two immediately consecutive contact blocks P ji, P j,i+1 of one and the same blade, the cross section of this bridge Pt ji being reduced relative to the cross section of the contact blocks P ji, P j,i+1, characterized in that said first and second blades (12,14) are made of magnetic material; and the surface S Ptji of the smallest cross section of the bridge Pt ji bearing out the following relationship: 0 < S Ptji < 2/3S Zi, in which j is an index identifying the blade and i is an index identifying the contact block of this blade. - the first blade comprising at least one contact block P 1i having a contact face F 1i, - the second blade comprising at least one contact block P 2i facing the contact block P 1i and having a contact face F 2i, the contact blocks P 1i and P 2i facing one another when the intersection of the face F 2i and of the projection in the transverse direction, at right angles to the longitudinal direction, of the face F 1i on the face F 2i forms an area of overlap whose surface S zi is strictly greater than zero, - at least one contact block of each pair of contact blocks P 1i, P 2i facing one another being able to be displaced in the transverse direction, under the effect of the magnetic field, between: • a closed position in which the faces F 1i and F 2i are directly in mechanical contact with one another to allow the passage of a current, and • an open position in which the faces F 1i and F 2i are separated from one another by an air gap to electrically insulate them from one another, • a closed position in which the faces F 1i and F 2i are directly in mechanical contact with one another to allow the passage of a current, and • an open position in which the faces F 1i and F 2i are separated from one another by an air gap to electrically insulate them from one another, - the first and second blades (12, 14) comprise contact blocks forming several pairs of contact blocks P 1i, P 2i facing one another, immediately consecutive in the longitudinal direction, and - each blade comprises at least one bridge Pt ji, each bridge directly mechanically linking two immediately consecutive contact blocks P ji, P j,i+1 of one and the same blade, the cross section of this bridge Pt ji being reduced relative to the cross section of the contact blocks P ji, P j,i+1, characterized in that said first and second blades (12,14) are made of magnetic material; and the surface S Ptji of the smallest cross section of the bridge Pt ji bearing out the following relationship: 0 < S Ptji < 2/3S Zi, in which j is an index identifying the blade and i is an index identifying the contact block of this blade. and the surface S Ptji of the smallest cross section of the bridge Pt ji bearing out the following relationship: 0 < S Ptji < 2/3S Zi, in which j is an index identifying the blade and i is an index identifying the contact block of this blade.