PURPOSE: To improve characteristics such as insulating and moisture resistances of the winding for the electric device by coating the surface of the winding with netlike fibrous insulator, immersing insulating varnish with netlike fibers, forming an insulating varnish coating between the net and the varnish, and preventing the varnish from flowing out therefrom by a simple method.

CONSTITUTION: Netlike fibrous insulator 1 is woven in predetermined net by heat resistant high molecular material such as polyester having excellent varnish immersing property and heat resistance. The insulator 1 is coated closely on the peripheral surfce of the winding end 3 of an electric device or the like, and the ends 3 thus coated are spirally wound and tightenend by insulator such as a string 4 or the like. It is then immersed with varinish and thermally cured at normal pressure or in vacuum to form rugged varnish coating 5A by the varnish surface tension on the net mesh 5 and the immersing property of the strands 2 of the insulator 1, to retain the necessary varnish amount thereon by immersing the varnish, and to prevent the varnish from flowing out therefrom by a simple method without using special device.