An active noise cancelling cord contains: a plug including a ground-wire conductor, a live-wire conductor, and a neutral-wire conductor; a socket including a protrusion in which a first receiving orifice, a second receiving orifice and a third receiving orifice are defined; and a noise reduction mode. The body is connected with a plug and a socket, and a shell is located between the plug and the socket. The conductive set includes a ground wire electrically connected with a ground-wire conductor and a first receiving orifice, a live wire electrically connected with a live-wire conductor and a second receiving orifice, a neutral wire electrically connected with a neutral-wire conductor and a third receiving orifice, a plug anti-noise wire electrically connected with a live-wire conductor, and the noise reduction mode, and a socket anti-noise wire electrically connected with the second receiving orifice and the noise reduction mode.