PURPOSE: To facilitate the demolishment and the cleaning after casting and greatly improve the workability by arranging a buffering material which is carbonized by bringing into contact with molten metal, between a pouring tube and pouring tube bricks in the inside, in the pouring tube for guiding the molten metal into a runner brick.

CONSTITUTION: The molten metal poured into the pouring tube 20 is flowed to a flowing hole 12a in the runner brick 12 through the pouring tube bricks 23 and poured into a mold 30 from the lower part. At that time, as the buffering pipe 24 is arranged between the pouring tube bricks 23 and an iron case 25 even if the molten metal is leaked from a joint part of the pouring tube bricks 23, the buffering pipe 24 brought into contact with the leaked molten metal is easily carbonized and the sticking of the molten metal to the pouring tube 20 is prevented. Therefore, the demolishment of the pouring tube 20 after casting is facilitated and further, as the sand is not filled between the pouring tube bricks 23 and the iron case 25, the cleaning work is facilitated and the working environment is improved.