To reduce abrasion by accumulating hard powder on a front face of an orifice, and forming a natural taper to squeeze a passage in an orifice shape suddenly changing to a small inside diameter part from a large inside diameter part.

In a nozzle, since a natural taper is formed by accumulating hard particles 8 coming flying in the beginning on a front face of an orifice 2, succeeding hard particles 8 collide with the hard particles forming this taper. Then, the hard particles 8 are continuously replaced a little, but in any case, the coming flying hard particles 8 do not directly collide with a metallic wall of the nozzle, and therefore, the nozzle is not abraded by being shaven. This nozzle is particularly useful as a nozzle to inject powder containing hard particles such as sand like quartz sand, pulverized powder of rock, ceramic particles such as alumina and powder of metal or alloy or an intermetallic compound.