PURPOSE: To obtain a beautiful and strong coating film by preventing air bubbles generated in the coating film, by applying a liquid containing a resin to one surface side of a hollow container while the container is simultaneously heated from the other surface side thereof.

CONSTITUTION: When the spray coating of a liquid paint is applied onto the surface of a matter such as a non-plastic hollow container, the liquid paint applied to one surface side 11f of plate shaped matter 11 by spraying is adhered to said surface to form a coating layer P2. Simultaneously with this coating work, the matter 11 is heated as shown by a character Hb from the side of the surface 11b opposite to the coated surface. The temp. of the matter 11 is raised by this heating and the heat of the matter 11 is further conducted to the coating layer P2 from the coated surface 11f to heat the liquid paint and the liquid contained in the liquid paint is evaporated by said heat to form air bubbles in the coating layer P2 but these air bubbles are gradually pushed to the surface side by the solidification action of the paint successively moved and advanced to the surface side and expelled to the open air at last and the presence of air bubbles in the coating layer P2 is eliminated.