An arc box and an electromagnetic contactor comprising same are disclosed. The arc box according to an embodiment of the present disclosure comprises a coupling protrusion. The coupling protrusion is inserted into and coupled to a grid coupling hole of an arc chamber. Therefore, the arc chamber can be stably coupled to the arc box. In one embodiment, the coupling can be performed through snap fastening. Therefore, the arc chamber and the arc box can be easily coupled. A rib part is formed on the arc box. The rib part is positioned to be adjacent to the coupled arc chamber so as to prevent pitching of the arc chamber. Therefore, the arc chamber coupled to the arc box can stably maintain a stopping state.