A method for producing a corona discharge-preventing structure for covering outer surface of a to-be-insulated object, the method comprising: a tape producing step of producing a corona discharge-preventing tape; a main insulating step of winding a main insulating tape around the to-be-insulated object; and a winding step of winding the corona discharge-preventing tape around the outer surface of the to-be-insulated object around which the main insulating tape has been wound, wherein the tape producing step has: a mixture producing step of producing a mixture by adding an electrically conductive powder and non-electrically conductive nanoparticles to a macromolecular polymer; a coating step of coating the mixture on a fiber-reinforced cloth; and a heating-drying step of heating and drying the fiber-reinforced cloth coated with the mixture; characterized in that the electrically conductive powder is carbon black and the macromolecular polymer is a liquid-state resin; the tape producing step further comprises a cutting step of cutting the fiber-reinforced cloth into tapes after the heating-drying step, thereby providing a fiber-reinforced tape; and the coating step has a step of passing the fiber-reinforced cloth in a liquid-state resin in which carbon black and the non-electrically conductive nanoparticles are mixed together. a tape producing step of producing a corona discharge-preventing tape; a main insulating step of winding a main insulating tape around the to-be-insulated object; and a winding step of winding the corona discharge-preventing tape around the outer surface of the to-be-insulated object around which the main insulating tape has been wound, wherein the tape producing step has: a mixture producing step of producing a mixture by adding an electrically conductive powder and non-electrically conductive nanoparticles to a macromolecular polymer; a coating step of coating the mixture on a fiber-reinforced cloth; and a heating-drying step of heating and drying the fiber-reinforced cloth coated with the mixture; characterized in that the electrically conductive powder is carbon black and the macromolecular polymer is a liquid-state resin; the tape producing step further comprises a cutting step of cutting the fiber-reinforced cloth into tapes after the heating-drying step, thereby providing a fiber-reinforced tape; and the coating step has a step of passing the fiber-reinforced cloth in a liquid-state resin in which carbon black and the non-electrically conductive nanoparticles are mixed together. a mixture producing step of producing a mixture by adding an electrically conductive powder and non-electrically conductive nanoparticles to a macromolecular polymer; a coating step of coating the mixture on a fiber-reinforced cloth; and a heating-drying step of heating and drying the fiber-reinforced cloth coated with the mixture; characterized in that the electrically conductive powder is carbon black and the macromolecular polymer is a liquid-state resin; the tape producing step further comprises a cutting step of cutting the fiber-reinforced cloth into tapes after the heating-drying step, thereby providing a fiber-reinforced tape; and the coating step has a step of passing the fiber-reinforced cloth in a liquid-state resin in which carbon black and the non-electrically conductive nanoparticles are mixed together.