PURPOSE: To provide a winding for a stationary induction apparatus winding excellent in impulse voltage resistance wherein initial potential between coils is linearly distributed without degrading the winding workability of conventional disc coils comprised of interleave windings.

CONSTITUTION: A coil conductor coating material 20A for coil conductors 11A, 11B comprising disc coils 1e composed of interleave windings, is an insulating material the dielectric constant of which is gradually decreased from the line terminal U to the terminator V of the coil. Thereby the potential gradient between the line terminal side coils is reduced, and the distribution of potential between the disc coils is unified.