PURPOSE: To prevent a sliding gate from becoming high temp. and loss of magnetic flux by interposing a magnetic shut-off plate fitting ventilating means 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 gate 7 does not receive the effect of the magnetic flux. Therefore, loss of the magnetic flux at the sliding gate is eliminated. Further, as the heat is conducted from the magnetic shut-off plate 8 with the air, the low temp. condition can be maintained.