PURPOSE: To prevent adhesion of powder to each other by vibrating injected powder beams.

CONSTITUTION: High pressure fluid is injected against a solid gas two-phase mixture flow conveying pipe 2 through a fluid feed pipe 5 and powder is fed through a particulate feed pipe 7 to the solid gas two-phase mixture flow conveying pipe 2. High pressure fluid and powder are mixed together in the solid gas two-phase mixture flow conveying pipe 2 to produce a solid gas two- phase mixture flow, which is conveyed to a first nozzle 9 and accelerated by the first nozzle 9 and delivered as an acceleration flow to a second nozzle 13. The acceleration flow forms a parallel flow by means of the nozzle part 14a of the second nozzle and through excitation of the exciting part 16 of the second nozzle 13, powder passing through the nozzle part 14a is excited and injected as powder beams to a work. Thus, the powder beams are uniformized without being coagulated and adhered to each other and microprocessing of the work is practicable.