The optimum gating system for manufacturing turbine housing is designed in this study, and a heater as heat source is provided to the riser, attempting to reduce its size. In the case where the runner is divided into two branches, a symmetrical gating system is adopted so that the two products could be produced in one process. Furthermore, cross-sectional shapes of the sprue, runner, and gate are designed by setting the sprue:runner:gate ratio at 1:0.9:0.6. A casting analysis is then conducted to investigate the effects of shape of the riser, sleeve material, temperature of the heater, and provision of insulation material at the top of the riser. The conditions obtained from the analysis are applied to the experiment. Hot spot defects calculated by casting simulation are reduced when sand sleeve material, straight type riser, open top sleeve, and more than 600°C of heater temperature are used. It is possible to produce a casting with almost no surface defects by adopting a riser with a size of 10–20 mm and a heater of 600°C–700°C. A casting recovery rate of 80% is achieved and, regarding mechanical properties, its tensile strength is 534 MPa, its elongation rate is 9%, and its Brinell hardness is 170 HB.