PURPOSE: To sufficiently enhance the adhesion of a coating film applied on the surface of a steel sheet to the steel sheet and to stably enhance the leveling property of the coating material applied on the surface of the steel sheet relating to the method for forming the org. insulating film consisting of a water-soluble resin which is used for coating the surface of the steel sheet and has the excellent adhesion.

CONSTITUTION: The temp. (x) of the steel sheet just before the application of the water-soluble resin is set and controlled at and to ≥0.85y+8.5(°C) according to the viscosity (y) (Ford Cup #4) of the water-soluble resin within a range from 10 to 100°C at the time of applying the water-soluble resin on the surface of the steel sheet via a roll coater and forming the org. insulating film thereon by heating and baking the coating film, by which the good correlative relation between the temp. of the steel sheet and the viscosity of the water-soluble resin in order to form the extremely thin insulating film on the surface of the steel sheet is obtd.