A contactor assembly is disclosed comprising a case having a plurality of serially and vertically sectioned pole chambers, each provided with a traveling contact and a pair of operation frames. A traveling contact bar having right and left arm portion is pivotally fixed on a support frame. The operation frames are installed at right and left positions of the traveling contact, and each frame is provided with a window and a leg portion extending from a lower surface of the frame. A pair of upper and lower contact springs are provided in the window, and the adjacent arm portion of the traveling contact extends through the window and is sandwiched by the pair of contact springs. The pair of right and left operation frames are interlockingly connected at the lower ends of both the legs. An electromagnet is connected to each leg and a return spring is provided on the lower surface of the frame. At least one traveling contact terminal is provided at each tip of the arm portions of the traveling contact bar, and a stationary contact terminal is provided in the path of the traveling contact terminals. At least one connecting terminal is provided at each side of the pole chamber.