An exemplary switching device for an electric circuit, including at least one contact movable between a closed position in which it is coupled to a corresponding fixed contact and an open position in which it is spaced away from said corresponding fixed contact. A main shaft suitable for rotating about an axis and operatively connected to said at least one movable contact so as to cause with its rotation the movement of said at least one movable contact between the open and closed positions. The switching device includes a locking device which has one or more parts coupled to and which is configured for directly acting on the main rotating shaft and locking said at least one movable contact in the open position.