PURPOSE: To prevent the leakage of molten metal and to improve the yield of the molten metal by screwing an adjusting pipe at least at one end of a main pipe.

CONSTITUTION: A recessed groove 10a is formed in the longitudinal direction of a bottom plate 10 and runner bricks 12 are set there through a liner 11. A communicating hole 12a is formed in the inner parts of the runner bricks 12. A runner brick holding jig 50 is arranged between the end part 12b of the runner brick 12 and the end part 10b of the bottom plate 10. The holding jig 50 is provided with the main pipe 51 and the adjusting pipes 52, 52 at both ends thereof and made of e.g. iron. Further, in the intermediate of the main pipe 51, setting plates 53, 53 for setting the holding jig 50 to a prescribed position of the recessed groove part of the liner 11 are fitted. The holding jig 50 changes the screwing distance by rotating the adjusting pipe 52 to adjust the length corresponding to the length of a gap. Thus, the runner brick is surely held and the development of the gap can be restrained.