An ash melting system of the present invention includes a slagging combustion furnace (10) for melting ash into molten slag; and a slag separating apparatus (50) for bringing the molten slag (121) discharged from the slagging combustion furnace into contact with slag cooling water (152) to produce water-quenched slag (122), and separating the water-quenched slag from the slag cooling water. The ash melting system further includes a gas blowing means for blowing air or inert gas (132) between a slag discharge port (14) of the slagging combustion furnace and the surface of the slag cooling water.