PURPOSE: To prevent the generation of splashes at the start of casting by providing a riser brick constituted in such a manner that the sectional area in the bottom of a molten metal inflow port and the sectional area at the top thereof satisfy the specific relation to a stool brick.

CONSTITUTION: The riser brick is provided with a runner 4 and the inflow port 5 connecting thereto. The section of the inflow port 5 is constituted to an expanding shape with which the sectional area S0 in the bottom 7 and the sectional area S1 at the top 8 satisfy the relation S1>S0. The section of the inflow port 5 is preferably ≥1.5 S1/S0. One inside diameter D1 of the section of the top 8 and the other inside diameter D2 orthogonal therewith are preferably D1≠D2. The generation of the splashes in the starting stage of casting is thus prevented.