PURPOSE: To form a high-quality coating by using many kinds of raw materials by making a high-velocity thermal spray apparatus include a powder raw material injector assembly which extends into a raw material injector assembly receiving hole and a barrel which is located within the central hole and has a discharge end and a suction end adjacent to the discharge face of a fuel/ gaseous oxidizer nozzle.

CONSTITUTION: A passage 104 extending through the main body of the fuel- gaseous oxidizer composite nozzle 42 extends from the discharge port 100 to the perpendicular hole or the suction port 106. The suction port 106, the passage 104 and the discharge port 100 form continuous, discrete and separable gaseous oxidizer passages via the fuel-gaseous oxidizer composite nozzle 42. The discharge face 98 of the fuel-gaseous oxidizer composite nozzle 42 regulates, together with the position of the discharge port 100, an outside region 112 to which the annular shoulder 114 of the barrel structure 80 is coupled. The discharge port 100 is thus not limited and the direct discharge of the fuel and the gaseous oxidizer to the passage 116 of the barrel 80 is possible. Then, combustion is effected within the passage 116 of the barrel 80.