PURPOSE: To let opening at the tapping be effected smoothly by packing refractory material in the tuyeres, upper nozzle and upper plate of the sliding nozzle of a molten steel vessel and further covering the surface thereof with amorphous refractory material.

CONSTITUTION: A sliding nozzle is installed to the tapping port at the bottom of the ladle or the like for containing molten steel, with the object of controlling the effluent rate of molten steel. At this time, the tapping port is held closed by moving the lower plate 5 and lower nozzle 7 of the plate and refractory material is packed from the top end of the tuyere 9 to the contact interface of the upper and lower plates. For this refractory material is used the refractory granular mixture of Al2O3 or MgO base which does not sinter even when heated for more than 1hr at 1500°C or more. It is packed to the height of 10W100mm from the top end of the tuyere downward. Next, amorphous refractory material such as castable refractory and plastic refractory is coated thereon within the tuyere 9 to the thickness of 10W 100mm. The filler is not sintered by the charged molten metal and molten metal readily flows out through the tapping port owing to the movement of the lower plate 5 and lower nozzle 7.