PURPOSE: To effect uniform adsorption of a coating material to the inner wall of the subject vessel by using ionized gas in the spraying of a coating material from a nozzle to the inner wall, thereby eliminating the flotation of the coating material in the form of mist.

CONSTITUTION: A corona discharge is generated in a space A surrounded by the inner surface of a case simultaneous to the spray of a coating material from a nozzle 3 in the form of mist. The gas in the space A is ionized by this process and the coating material particle is charged by the collision of the ion to the coating material particle floating in the form of mist. The charged particle is pulled by electrostatic force toward the case 9 charged to opposite polarity to achieve the deposition of the coating material to the inner surface of a case for the forming of a food such as bread and cake.