To provide an apparatus and a system for restraining fine wave motion of molten metal developed on a meniscus surface when fluidity of the molten metal is controlled.

The apparatus for controlling the fluidity of the molten metal, is provided with an immersion nozzle for pouring the molten metal at the upper part, a mold for producing a metallic slab when the molten metal poured from the immersion nozzle is solidified and made to solidified shell, and an electromagnetic stirring device for fluidizing the molten metal by giving a linear motor action with an electromagnetic induction in the mold. Electric coils for generating DC magnetic field in vertical and upward directions provided at the positions of the meniscus surface of the mold and a spouting hole of the nozzle, respectively, and DC current is given to these coils and the DC magnetic field having desirably 0.05-0.1 tesla or 0.05-0.2 tesla is given and in this way, the fluctuation wave motion of the molten metal developed at the electromagnetic stirring time, is restrained.