PURPOSE: To facilitate the adjustment of the operating conditions and to produce a fine grain of a compd. by heating and evaporating a raw material and passing the formed fine grain together with both an inert gas and a reaction gas for forming a compd. to a plasmatic region to allow these to react each other.

CONSTITUTION: Gaseous mixture of an inert gas and a reaction gas for forming a compd. is continuously sent through a valve 5 to the inside of a vacuum- exhausted vacuum vessel 1. A microwave oscillator 21 is actuated and microwave is given to the inside of a flow pipe 16 to form a plasmatic region 31. On the other hand, electricity is conducted to a supporting board 13 of a raw material from an electric power source 15 to perform heat release and the raw material 14 is successively evaporated and a fine grain of the raw material 14 is formed in the neighborhood. This fine grain is flowed into the flow pipe 16 together with a gaseous mixture and reached to the plasmatic region 31. In this region 31, the fine grain of the raw material is risen in temp. by absorbing microwave energy and also the reaction gas is made plasmatic by microwave and activated. Therefore both react with each other and the fine grain of the raw material is made a compd. and the fine grain of the compd. is obtained.