PURPOSE: To provide a tuyere, in which the service life of the tuyere executing change of flow rate by using a movable core is extended, the enlargement in the flow rate range is executed and costs of gas and the tuyere can drastically be reduced.

CONSTITUTION: The flow rate control range is enlarged by shifting the core 3 inserted into the inner part of the tuyere 1 contracted in tapered state at the tip part to change gas passage cross sectional area. At this time, pressure loss range at the time of working the core, is drastically shortened and the clogging of the tuyere caused by the penetration of molten metal can be prevented by using the tapered state tuyere 1, and the efficient injection of powdery material can be applied.