To provide a structure to improve the thermal shock resistance of a glass pipe, having a characteristic causing less trouble in structuring and in production engineering, requiring less cost, and imposing no special requirement in seeking the availability of materials to be used.

The structure 2 comprises the glass pipe 1 in which an internal member 3 is inserted. The internal member 3 is formed as a pipe 19 having a thin wall. The hollow part surrounded by the internal member 3 is hydrodynamically connected to the inner chamber 10. The wall thickness S3 of the internal member 3 is thinner than the wall thickness of the glass pipe 1, and the internal member 3 is, at least partially, free from the direct thermal connection with the glass pipe 1 when liquid is flowing in the glass pipe 1.