PURPOSE: To uniformly compound a powder material, by mounting one or more introducing pipe for introducing a fine powder-containing gaseous raw material from the tangential direction of the outer peripheral part of a plasma stream to the downstream side in the vicinity of the plasma generation part of a plasma generating container.

CONSTITUTION: Plasma is generated in a plasma generating container 1 by a plasma generator 13, and carbon compound gas and silicon compound gas are introduced into said container 1 from a gaseous raw material introducing pipe 4. Whereupon, a silicon carbide ultrafine powder with a particle size of about 0.005W0.01μm can be formed at the almost center of the plasma generating container 1. At the same time, when gaseous raw materials and a Si fine powder with a particle size of about 0.5W1μm from a microfeeder 3 are introduced into the container from a fine powder introducing pipe 2, said fine powder spirally flows in the aforementioned ultrafine powder stream and both of them are uniformly mixed to be accumulated on a stainless steel vat (collector) 11 in a uniformly mixed state.