A high strength steel sheet having a chemical composition in mass% containing: C: 0.06% or more and 0.14% or less, Si: 0.1% or more and 1.5% or less, Mn: 1.4% or more and 2.2% or less, P: 0.05% or less, S: 0.0050% or less, Al: 0.01% or more and 0.20% or less, N: 0.10% or less, Nb: 0.015% or more and 0.060% or less, and Ti: 0.001% or more and 0.030% or less, contents of S, N and Ti satisfying Formula below, optionally one of, or two or more of Cr: 0.01% or more and 0.15% or less, Mo: 0.01% or more and less than 0.10%, and V: 0.001% or more and 0.065% or less optionally B: 0.0001% or more and less than 0.002%, optionally one of or two of Cu: 0.001% or more and 0.2% or less, and Ni: 0.001% or more and 0.1% or less, and optionally Ta, W, Sn, Sb, Ca, Mg, Zr or REM, with the content of each of these elements being 0.1% or less, a balance being Fe and an inevitable impurity, comprising, in terms of area fraction relative to an entire steel microstructure, 30% or more and 100% or less ferrite, 0% or more and 70% or less martensite, and less than 20% in total of pearlite, bainite and retained austenite, and the ferrite containing, in terms of area fraction relative to an entire microstructure, 0% or more and 10% or less non-recrystallized ferrite, with a difference between a maximum value and a minimum value of the area fraction of the non-recrystallized ferrite in a longitudinal direction of the steel sheet of 5% or below: % Ti − 48 / 14 % N − 48 / 32 % S ≤ 0.0000, in Formula, [%Ti] represents content (mass%) of component element Ti, [%N] represents content (mass%) of component element N, and [%S] represents content (mass%) of component element S, the tensile strength of the steel sheet being 590 MPa or larger, and the difference between the maximum value and the minimum value of the yield ratio, ΔYR, in the steel sheet being 0.05 or smaller, wherein the tensile strength and the difference between the maximum value and the minimum value of the yield ratio ΔYR are determined in accordance with the specifics given in the description. C: 0.06% or more and 0.14% or less, Si: 0.1% or more and 1.5% or less, Mn: 1.4% or more and 2.2% or less, P: 0.05% or less, S: 0.0050% or less, Al: 0.01% or more and 0.20% or less, N: 0.10% or less, Nb: 0.015% or more and 0.060% or less, and Ti: 0.001% or more and 0.030% or less, contents of S, N and Ti satisfying Formula below, optionally one of, or two or more of Cr: 0.01% or more and 0.15% or less, Mo: 0.01% or more and less than 0.10%, and V: 0.001% or more and 0.065% or less optionally B: 0.0001% or more and less than 0.002%, optionally one of or two of Cu: 0.001% or more and 0.2% or less, and Ni: 0.001% or more and 0.1% or less, and optionally Ta, W, Sn, Sb, Ca, Mg, Zr or REM, with the content of each of these elements being 0.1% or less, a balance being Fe and an inevitable impurity, comprising, in terms of area fraction relative to an entire steel microstructure, 30% or more and 100% or less ferrite, 0% or more and 70% or less martensite, and less than 20% in total of pearlite, bainite and retained austenite, and the ferrite containing, in terms of area fraction relative to an entire microstructure, 0% or more and 10% or less non-recrystallized ferrite, with a difference between a maximum value and a minimum value of the area fraction of the non-recrystallized ferrite in a longitudinal direction of the steel sheet of 5% or below: % Ti − 48 / 14 % N − 48 / 32 % S ≤ 0.0000, in Formula, [%Ti] represents content (mass%) of component element Ti, [%N] represents content (mass%) of component element N, and [%S] represents content (mass%) of component element S, the tensile strength of the steel sheet being 590 MPa or larger, and the difference between the maximum value and the minimum value of the yield ratio, ΔYR, in the steel sheet being 0.05 or smaller, wherein the tensile strength and the difference between the maximum value and the minimum value of the yield ratio ΔYR are determined in accordance with the specifics given in the description.