A high-strength austenitic stainless steel, which has good hydrogen embrittlement resistance and hydrogen fatigue resistance, has a chemical composition including, in mass %, C: up to 0.10%; Si: up to 1.0%; Mn: not less than 3.0% and less than 7.0 %; Cr: 15 to 30%; Ni: not less than 12.0% and less than 17.0%; Al: up to 0.10%; N: 0.10 to 0.50%; P: up to 0.050%; S: up to 0.050%; at least one of V: 0.01 to 1.0% and Nb: 0.01 to 0.50%; and other elements, the balance being Fe and impurities, wherein the ratio of the minor axis to the major axis of the austenite crystal grains is greater than 0.1, the crystal grain size number of austenite crystal grains is not lower than 8.0, and the tensile strength is not less than 1000 MPa.