A power switching device including a fixed contact, a movable contact, an arc runner for transferring a leg of an electric arc to the outside of the fixed contact, a U-shaped fixed contactor electrically connected to the fixed contact, and a deionizing grid for extinguishing the arc. The side of the fixed contact is opposed to the side of the arc runner in three directions. At least the portion of the arc runner close to the fixed contact is kept away from the fixed contact and is physically separated therefrom by an electrically insulating medium. The arc runner is fixed and connected to a portion of the fixed contactor which is on the opposite side of the deionizing grid with respect to the fixed contact. Further, the runner extends so that it forms a continuous path along which the arc runs. Accordingly, after the arc has been transferred to the runner, it is urged toward the deionizing grid, thereby assuring continuous and smooth movement of the arc. Thus, a situation in which the arc is moved away from the grid resulting in incomplete extinction of the arc is prevented.