PURPOSE: To enable optimum pouring with a simple device without requiring a large-scale device with a device provided with a means for driving the stopper of a nozzle in the bottom at the top end of a spout-shaped tap hole of which the molten metal surface is controlled by controlling steplessly the stopper drive.

CONSTITUTION: When the input current value of a DC power source 31 is adequately varied and is passed to a pneumatically operated controller 32, the current is transduced to an air pressure by as much as the current value in the controller 32. The piston rod 8a of an air cylinder 8 is vertically moved by such air pressure. The displacement of the vertical movement is transmitted via a feedback lever 33 to the controller 32 and the rod 8a is stopped in the position balanced with the power generated by the input current. The vertical stroke of the cylinder hence the vertical driving stroke of the stopper 7 of a nozzle 6 in the bottom at the top end of a spout-shaped tap hole coupled directly to the rod 8a are thus steplessly controlled. As a result, the molten metal is poured with good accuracy in an optimum pouring pattern into various casting molds having intricate shapes and having high or low pouring rates.