Disclosed is a heat resistant austenitic cast steel consisting essentially of 0.03 to 0.09% by weight of carbon, 2.0% by weight or less of silicon, 3.0% by weight or less of manganese, 0.11 to 0.30% by weight of nitrogen, 6 to 15% by weight of nickel, 15 to 19.5% by weight of chromium, 0.01 to 1.0% by weight of vanadium, 1 to 5% by weight of molybdenum, and the balance of iron. The heat resistant austenitic cast steel exhibits excellent mechanical properties such as mechanical strength, elongation, reduction of area and fracture time caused by creep fracture, particularly, under high temperatures. If a turbine casing is formed of the cast steel, it is possible to increase the steam temperature and pressure.