Abstract: A mono or bidirectional contactor device for applications involving switching of the power supply for high current and/or voltage electrical loads, of the type comprising a containing and protective casing made of synthetic plastic insulating material with a bottom wall from which there extends an actuator portion, comprising a coil and auxiliary contacts, an intermediate portion for housing fixed and movable contact poles, and an upper arc chute portion for dissipating the electric arc. Advantageously the casing is chosen so as to have a flat parallelepiped form with the bottom wall extending at 90° with respect to a side wall of the casing on the shorter side and a support plate for the contactor is connected to the outer surface of the base wall or of said side wall so as to support the casing substantially with a vertical extension from the horizontal plane or projecting from the vertical plane.