Abstract: An electrostatic spray coating method where an electrical field is generated between a spray gun and an object for electrostatically attracting the paint to the object for coating the same. A positive or negative voltage is preliminarily applied to the object through a clamping device disposed on a floor face of a spray booth with the spraying system for spraying the paint from the spray gun being electrically grounded while the object is maintained electrically insulated by suspending it from a hanger rod with an insulator of a hanger conveyor type installed in the spray booth.