A method of evaluating a residual stress, the method comprising: applying, to a specimen, a biaxial tensile residual stress including an uniaxial tensile residual stress or an iso-directional tensile residual stress, and then performing an instrumented indentation test using an indenter; calculating a maximum indentation depth h t 0 in a stress-free state of the specimen by substituting, into an equation for calculating a maximum indentation depth in a stress-free state, an actual contact depth h c 0 in a stress-free state, obtained from actual contact depth h c T of the indenter and a maximum indentation depth h t T and a final depth h f T under a maximum indentation load L 0 of the indenter, which are acquired from an indentation load-indentation depth curve obtained through the instrumented indentation test, said equation being: h c 0 h t 0 = 9.9 × 10 3 h t 0 h t T − h f T + 1.0; acquiring an indentation load-indentation depth curve in a stress-free state by substituting the calculated maximum indentation depth h t 0 in a stress-free state of the specimen into the following indentation load-indentation depth correlation equation: L 0 = k h t 0 2 wherein k denotes a fitting coefficient, and calculating a load difference Δ L between a load L 1 corresponding to the maximum indentation depth h t T in the indentation load-indentation depth curve in the stress-free state and the maximum indentation load L 0; and calculating a residual stress σ res x + σ res y of the specimen by substituting the calculated load difference Δ L into the residual stress calculation equation: σ res x + σ res y = 3 Ψ Δ L A c, wherein A c denotes an actual contact area of the indenter and Ψ denotes a plastic restraint coefficient. applying, to a specimen, a biaxial tensile residual stress including an uniaxial tensile residual stress or an iso-directional tensile residual stress, and then performing an instrumented indentation test using an indenter; calculating a maximum indentation depth h t 0 in a stress-free state of the specimen by substituting, into an equation for calculating a maximum indentation depth in a stress-free state, an actual contact depth h c 0 in a stress-free state, obtained from actual contact depth h c T of the indenter and a maximum indentation depth h t T and a final depth h f T under a maximum indentation load L 0 of the indenter, which are acquired from an indentation load-indentation depth curve obtained through the instrumented indentation test, said equation being: h c 0 h t 0 = 9.9 × 10 3 h t 0 h t T − h f T + 1.0; acquiring an indentation load-indentation depth curve in a stress-free state by substituting the calculated maximum indentation depth h t 0 in a stress-free state of the specimen into the following indentation load-indentation depth correlation equation: L 0 = k h t 0 2 wherein k denotes a fitting coefficient, and calculating a load difference Δ L between a load L 1 corresponding to the maximum indentation depth h t T in the indentation load-indentation depth curve in the stress-free state and the maximum indentation load L 0; and calculating a residual stress σ res x + σ res y of the specimen by substituting the calculated load difference Δ L into the residual stress calculation equation: σ res x + σ res y = 3 Ψ Δ L A c, wherein A c denotes an actual contact area of the indenter and Ψ denotes a plastic restraint coefficient.