PURPOSE: To provide an opening/closing valve used in conjunction with an electromagnetic flow control device and adjusting the flow of liquid metal flowing through an orifice.

CONSTITUTION: An opening/closing valve 10 is provided with an electrically conductive slider plate 26 which is positioned sufficiently close to an electromagnetic flow control device 8 to be inductively heated by the electromagnetic field generated thereby. The opening/closing valve permits the flow of liquid metal to be selectively stopped and started as desired. The combination of the opening/closing valve and the electromagnetic flow control device is suitable for open type vessel pouring operation in a continuous casting facility.