A heat-resisting steel contains 0.08 to 0.15 percent by weight of carbon, over 0.2 to 0.6 percent of silicon, 0.3 to 0.8 percent of manganese, 0.6 to 1.2 percent of nickel, 9.5 to 11.0 percent of chromium, 0.7 to 1.5 percent of molybdenum, 0.15 to 0.27 percent of vanadium, 0.10 to 0.27 percent in total of niobium and/or tantalum, 0.03 to 0.08 percent of nitrogen, over 1.1 to 1.3 percent of tungsten, and iron for the remainder. The creep rupture strength of this heat-resisting steel is much higher than that of a prior art 12-Cr heat-resisting steel. A turbine component formed of the heat-resisting steel of the present invention has enough strength for use at a high temperature of 600.degree. to 650.degree. C.