PURPOSE: To prevent the defects of spray-coated film from occuring by applying an air jet to near the spray coating point thereby blowing off the unmolten fine powder around the spraying jet.

CONSTITUTION: An air jet 3 is applied to the surface 2 to be sprayed of the work 1, from the direction opposite from the spray coating direction. Unmolten fine powder flow 6 exists around the central part (high temperature high speed part) 5 of a plasma jet 4. When the air jet 3 is applied, the unmolten powder is blown off and this powder is prevented from being included in the film. Hence, the film becomes uniform, the gun distance (spray coating distance) is made smaller and the melt sticking efficiency is improved.