PURPOSE: To prevent a sliding gate from becoming high temp. and loss of magnetic flux by interposing a magnetic shut-off plate providing water passage for passing cooling water between an induction heating coil and the sliding gate in a molten metal tapping device at lower end of a nozzle in a vessel charging molten metal.

CONSTITUTION: In the case of tapping the molten metal in the vessel 3, the sliding gate 7 is opened and also the metal in the nozzle 5 is induction-heated, to easily tap the molten metal from the vessel 3. Further, as the magnetic shut-off plate 8 for preventing the magnetic flux generated from the induction heating coil 6 is interposed at between the induction-heating coil 6 and the sliding gate 7, the sliding nozzle 7 does not receive the effect of the magnetic flux. Therefore, loss of the magnetic flux at the sliding nozzle 7 is eliminated. Further, as the heat is conducted from the magnetic shut-off plate 8 with the cooling water, the low temp. condition can be maintained.