The invention relates to a swinging-arm three-pole on-off device of an earth leakage protective socket, which belongs to the technical field of protective devices of low-voltage electrical apparatus, and comprises a base, a contact mechanism which is formed by a ground wire contact pair, a live conductor contact pair and a neutral conductor contact pair, a circuit board, an electromagnetic trip drive mechanism, a trip mechanism and a reset push button. The invention is characterized by further comprising a swing frame which is arranged on the base, the swing frame is connected with the trip mechanism, and one side of one end of the swing frame is corresponding to and matched with the live conductor contact, and the other side is corresponding to and matched with the neutral conductor contactor, and the middle portion of the other end of the swing arm is corresponding to and matched with a ground wire contact. The invention has the advantages that the swinging-arm three-pole on-off device can achieve the interlocked closing and disconnecting of a ground wire, a live conductor and a neutral conductor, and the ground wire contact can be closed before the live conductor contact and the neutral conductor contact when in closing, and the live conductor contact and the neutral conductor contact are disconnected before the ground wire contact when in breaking, and the swinging-arm three-pole on-off device is beneficial for fully playing the function of protecting electric apparatus and personal safety.