To provide a slag discharge port structure for a gasifier which prevents a molten slag from being detoured to a back surface of the slag discharge port so as not to form an icicle-like forming product without deterioration of slag fluidity by sufficiently receiving a radiation heat from the gasifier interior and maintaining a temperature of the slag and which can stably and continuously discharge the slag.

The gasifier gasifies a carbonaceous material by an oxidizer and generates a high-temperature gas. The slag discharge port structure for the gasifier discharges the molten slag obtained by melting an ash content of the gasified carbonaceous material gasified by the gasifier. The slag discharge port structure comprises a spindle-like fin 11 made of a metal inclined at an angle for allowing the slag to flow down to an embedded water-cooled tube 10 for constituting a slag discharge port 4 by maintaining the fluidity of the slag by a radiant heat.