A magnetron plasma etching system has a plurality of processing chambers connected to a common transfer chamber. Each processing chamber has a pair of counter electrodes for generating an electric field and a magnet mechanism for generating a magnetic field having an N-S axis crossing the electric field. All magnetic fields are rotated in the same plane. The rotation of the magnetic fields is controlled by a controller. When one of the magnetic fields is rotated, the other magnetic fields are rotated at equal speed such that the directions of N-S axes thereof are parallel and identical to that of the one of the magnetic fields.