A superconducting apparatus includes a cryogenic chamber, superconducting equipment contained in the cryogenic chamber and a lead secured to the cryogenic chamber and connected to the superconducting equipment. A structured member for a prevention of an electric discharge is provided between the lead and an area for securing the lead of the cryogenic chamber. The structured member for the prevention of electric discharge may be a laminate of a conducting layer and a insulating layer having recoverable and non-recoverable insulation, and have an effect of shielding the corresponding lead from electromagnetic noises.