A nickel-base single-crystal superalloy, essentially consists of, in percentages by weight, 4.0% to 11.0% of cobalt, 3.5% to less than 5.0% of chromium, 0.5% to 3.0% of molybdenum, 7.0% to 10.0% of tungsten, 4.5% to 6.0% of aluminum, 0.1% to 2.0% of titanium, 5.0% to 8.0% of tantalum, 1.0% to 3.0% of rhenium, 0.01% to 0.5% of hafnium, 0.01% to 0.1% of silicon, and a balance being nickel and inevitable impurity, a total amount of rhenium and chromium being not less than 4.0% and a total amount of rhenium, molybdenum, tungsten and chromium being not more than 18.0%.