PURPOSE: To provide an injector for introducing fine grain material into bath in a dry type metallurgical vessel through an existing tuyere.

CONSTITUTION: An existing mechanical puncher is removed and exchanged with the injector 10 fitted to the existing tuyere body 20 so as not to disturb the existing blast connection. The injector 10 having a housing for forming an annular space while surrounding the injector pipe 36 with a space intervened is inserted into the tuyere 14. The fine grain material can be introduced through the pipe by blowing the compressed fluid into the annular space opening the tuyere 14.