PURPOSE: To improve control accuracy, by a method wherein six pairs of exciting coils for a cylindrical solenoid pump are divided into two groups of three pairs of the same while a controller for holding the level of molten metal is made independent.

CONSTITUTION: An immersion type cylindrical solenoid pump 15 is dipped into the holding furnace 16 of molten metal and the pump 15 is connected to an injection sleeve 13 through a molten metal supplying pipeline 17. The exciting coils of the pump 15 are divided into two parts of molten metal level holding coils 1∼3 and molten metal supplying coils 4∼6. These coils are connected to different controlling units 9∼10 respectively and, further, are connected to a controller 11, accommodating a micro-computer, through an interface 12. A molten metal level detector 7 for detecting the change of the level of the molten metal continuously is provided while the output of the detector is inputted into the controller 11 through an amplifier 8 and an A/D converter to control a molten metal level holding coil controller 8. An exciting current, necessary for molten metal supplying coils 4∼6, is controlled whereby a predetermined amount of molten metal is supplied to the injection sleeve 13.