A conduit structure for molten glass, a conduit system for molten glass, a vacuum degassing apparatus and a method for vacuum-degassing molten glass by use of the vacuum degassing apparatus, which are capable of effectively removing components eluted from a refractory brick forming a conduit for molten glass, foreign substances generated in the interface between molten glass and a platinum wall surface forming a conduit for molten glass, a bubble remaining in a surface layer of molten glass, a glass material denatured by volatilization, and the like, are provided.A conduit structure for molten glass, which is formed of a hollow pipe made of platinum or a platinum alloy, includes a double-pipe structure disposed in at least a downstream portion of the conduit structure, the double-pipe structure being formed of an inner pipe and an outer pipe; the inner pipe having an upstream end and a downstream end formed as open ends; the outer pipe having a downstream end formed as a closed end in a region located in a gap between the inner pipe and the outer pipe and as an open end in a region located in the inner pipe in the double-pipe structure; the conduit structure having an upstream end formed as an open end; and the outer pipe having an opening formed in a portion close to the downstream end thereof.