PURPOSE: To improve the quality of a casting by arranging a pattern for casting having draft downward, juxtaposing a pattern for pouring cup and down sprue having draft upward and drawing both patterns to reverse direction, respectively, after molding casting sand and forming the cope.

CONSTITUTION: With a simple process only by drawing the pattern for casting and the pattern for pouring cup 1 and down sprue 2 to the reverse direction, the reverse tapered sprue providing the pouring cup and the down sprue part at the same time, can be molded. Further, as the pouring cup and down sprue formed in the mold have shape extending upward, gas is not involved in the down sprue at the time of pouring the molten metal. Further, since the disturbance of the poured molten metal is prevented and the molten metal flows smoothly, the float-up and separation of inclusion in the runner is promoted. By this method, the quality of casting can be drastically improved and further, as the reverse tapered down sprue can be molded with the simple process, the molding cost can be suppressed to a low cost.