PURPOSE: To make molten steel in a mold the prescribed level and to control drift of molten steel to restrain by adjusting opening degree of a sliding nozzle with a hydraulic cylinder and position of a submerged nozzle.

CONSTITUTION: In the sliding nozzle 3, the molten steel 6 is poured while adjusting the opening degree with a hydraulie cylinder 12 so that mainly the molten steel 6 surface in the mold 2 becomes the prescribed level. Further, on the other hand, in the submerged nozzle 4, the position is adjusted indepen dently with the sliding nozzle 3 with the hydraulic cylinder 12 so that the main flows down into the center part of the inner hole of the submerged nozzle 4. In this method, the main flow of the molten steel 6 is uniformly distributed into the discharged holes 5 at right and left and the drift of the molten steel 6 poured into the mold 2 is restrained. In this result, the clogging of the sub merged nozzle 4 is reduced in a half, and multi-sequential continuous casting can be not only executed, but also the cast slab without any defect can be stable produced.