To stably discharge molten objects without causing deposit by preventing formation of a local low temperature part in a melting basin interior and preventing ununiformity of heating temperature when discharging melted objects from an outflow opening of the melting basin.

The device comprises: a first conductive path 9 for connecting a non-service side electrode 3 to a transformer 6; a sharing conductive path 10 for connecting an in-service side electrode 4 to the transformer 6; and a second conductive path 11 for connecting a bottom electrode 5 and the first conductive path 9. The device also comprises: a thyristor 12 in the first conductive path 9; and a thyristor 13 in the second conductive path 11. When melting the objects G in the melting basin 1 and discharging them from the outflow opening 2, switching control of electric power supply with respect to the first conductive path 9 and the second conductive path 11 is exclusively and alternately carried out by the thyristors 12, 13 to flatten a heating temperature of the melting basin 1 interior.