To provide a cooling device for slag pit water to efficiently cool slag pit water and rationally form a device related to a melt furnace.

A cooling device for melt furnace slag pit water 1 comprises a melt furnace slag pit 5 to store slag pit water 1 to cool molten slag 6; a slag pit water cooler 7 to cool the slag pit water 1; and a slag pit water circulation passage 8 having a slag pit water circulation passage 8 through which the slag pit water 1 is circulated throughout a range of from the melt furnace slag pit 5 to the slag pit water cooler 7. A slag pit water cooling mechanism 18 to cool the slag pit water 1 by cooling air arranged at the slag pit water cooler 7. A discharge passage K2 from the slag pit water cooling mechanism 18 is connected to a combustion air feed passage K to feed combustion air in a melt furnace 4.