There is provided a steel sheet including a chemical composition consisting of, in mass%: C: 0.14 to 0.60%, Si + Al ≤ 3.00, P ≤ 0.030%, S ≤ 0.0050%, N ≤ 0.015%, B ≤ 0.0050%, C × Mn ≤ 0.80, Mn + Ni + Cu + 1.3Cr + 4(Mo + W) ≥ 0.80, 0.003 ≤ Ti + Zr + Hf + V + Nb + Ta + Sc + Y ≤ 0.20, Sn + As + Sb + Bi ≤ 0.020, Mg: 0 to 0.005%, Ca: 0 to 0.005%, REM: 0 to 0.005%, with the balance: Fe and impurities, and satisfying Ms = 546 × exp(-1.362 × C) - 11 × Si - 30 × Mn - 18 × Ni - 20 × Cu - 12 × Cr - 8(Mo + W) ≥ 200, wherein a steel micro-structure includes, in volume%: martensite ≥ 85%, retained austenite ≤ 15%, and the balance: bainite, an average block size of martensite and bainite ≤ 3.0 µm, an average axial ratio of martensite and bainite: 1.0004 to 1.0100, and a yield stress is 1000 MPa or more.