PURPOSE: To control the pouring of molten metal by an electromagnetic pump precisely, by installing the second gain controller which changes and adjusts the gain on the basis of difference between the output of the first gain controller, which controls the pouring quantity with gain, and the output of a detector for molten metal level.

CONSTITUTION: When a casting mold 9 faces to the opening 4 for pouring molten metal of an electromagnetic pump, signal S2 is fed from a setting device 10 to the pump so as to pour molten metal. Slag is deposited on the internal wall of the hole for molten metal by the repetition of pouring of molten metal thereby reducing the flow of molten metal, so that only the gain of the gain controller 11a of a gain control unit 11 is increased. Hereby the output S2 of the setting device 10 is amplified to S' so as to compensate the shortage of pouring molten metal. When the feed quantity of molten metal per unit time is reduced because of the shortage of pouring quantity, the gain of the gain controller 11b increase and the input S3 is amplified to output side S3'. Hereby decrease in the actual efficiency of the electromagnetic pump 4 is compensated, and the pouring of the molen metal is continued ideally.