To provide a method which can prevent degrading of ingot surface skin and trapping of material covering the surface of molten steel in a bottom-pouring type ingot-casting mold, by reducing flow of shield gas bubbles swallowed in a pouring pipe into the bottom-pouring type ingot-casting mold, and preventing heavy boiling at the surface of molten steel in the bottom-pouring type ingot-casting mold, in the bottom-pouring type ingot-casting process using shield gas.

The method is used for leading the molten steel into a runner for bottom-pouring type ingot casting from a ladle through the pouring pipe 1, and comprises the steps of: pouring the molten steel from an upper inlet 4 of the vertical pouring pipe 1; turning the flow of molten steel to an end portion 3a of a stepping section 3, at the stepping section 3 located in a low end part 2 of the pouring pipe 1; turning further the flow of the molten steel to the lower part of a descending pipe 5 in the descending pipe 5; and turning the flow again to an exit 6 on the side wall of the descending pipe 5 which is located close and lower than the extension line of a bottom face 3b of the stepping section 3. In this way, the molten steel flowing from the exit 6 into the runner is given whirling flow and then led into the bottom-pouring ingot-casting mold through the bottom-pouring method, thereby improving the ingot surface skin.