To simply restrain the vibration of liquid surface and to improve the accuracy of poured molten metal quantity and the molten metal pouring pattern by executing the modeling with double pendulum system while using a vessel and the liquid surface therein as each of the pendulums and calculating a vessel tilting angle of the still liquid surface from a vessel tilting angle speed and a liquid surface vibrating angle speed.

Molten metal is poured by tilting a ladle 3 through a servo motor 5, and after completing the pouring of molten metal, the ladle 3 is quickly turned back and stopped to tilt the ladle. By this method, the molten metal is vibrated in the ladle 3. The ladle tilting angle θ1 with an encorder 7 and the molten metal vibrating angle θ2 with a liquid surface range finder 6, are detected and fetched into a computer 8 for control. Therein, the modeling of the double pendulums is executed by using the ladle 3 as the fist pendulum and the molten metal surface 4 as the second pendulum. A servo system is constituted by executing a linear approximation of the double pendulums at the last target position of this ladle 3. Further, the ladle tilting angle speed and the molten metal surface vibrating angle speed are calculated from θ1 and θ2, and the tilting angle of the first pendulum is calculated so as to still the second pendulum by executing the feedback, and the output voltage V of the servo motor 5 is obtd. based on this calculation to control the vibration of molten metal surface.