A cold-rolled steel sheet: containing, as the steel components, C: 0.10% to 0.20% (% means mass %, the same is applied hereunder), Si: 0.5% to 2.5%, Mn: 0.5% to 2.5%, and Al: 0.01% to 0.10% with the remainder consisting of iron and unavoidable impurities; and optionally N: 0.5% or less, V: 0.15° to or less, Mo: 0,5% or less, Cr: 0.8% or less, Cu: 0.5% or less, and B: 0.01% or less; having a structure comprising a mother phase structure of ferrite and a second phase structure of retained austenite and martensite (the martensite may not be included); and satisfying the following expressions and when the volume fraction of the ferrite in the whole structure is represented by Vf (%), the volume fraction of the retained austenite in the whole structure is represented by Vγ (%), the carbon content in the retained austenite is represented by Cγ (mass %), the shortest distance between the second phase structures is represented by dis (μm), and the average grain size of the second phase structures is represented by dia (μm), Vf × C γ × C γ × dis / dia ≥ 300 dis ≥ 1.0 μm wherein: the volume fraction Vf % of the ferrite in the whole structure is 60% or more; the volume fraction Vγ (%) of the retained austenite in the whole structure is 5.0% to 20%; the carbon content Cγ (mass %) in the retained austenite is 0.7% or more, and the average grain size dia (μm) of the second phase structures is 5 μm or less; wherein the shortest distance dis between the second phase structures and the average grain size dia of the second phase structures are measured on a cross sectional plane parallel with the rolling direction of the steel sheet. containing, as the steel components, C: 0.10% to 0.20% (% means mass %, the same is applied hereunder), Si: 0.5% to 2.5%, Mn: 0.5% to 2.5%, and Al: 0.01% to 0.10% with the remainder consisting of iron and unavoidable impurities; and optionally N: 0.5% or less, V: 0.15° to or less, Mo: 0,5% or less, Cr: 0.8% or less, Cu: 0.5% or less, and B: 0.01% or less; having a structure comprising a mother phase structure of ferrite and a second phase structure of retained austenite and martensite (the martensite may not be included); and satisfying the following expressions and when the volume fraction of the ferrite in the whole structure is represented by Vf (%), the volume fraction of the retained austenite in the whole structure is represented by Vγ (%), the carbon content in the retained austenite is represented by Cγ (mass %), the shortest distance between the second phase structures is represented by dis (μm), and the average grain size of the second phase structures is represented by dia (μm), Vf × C γ × C γ × dis / dia ≥ 300 dis ≥ 1.0 μm wherein: the volume fraction Vf % of the ferrite in the whole structure is 60% or more; the volume fraction Vγ (%) of the retained austenite in the whole structure is 5.0% to 20%; the carbon content Cγ (mass %) in the retained austenite is 0.7% or more, and the average grain size dia (μm) of the second phase structures is 5 μm or less; wherein the shortest distance dis between the second phase structures and the average grain size dia of the second phase structures are measured on a cross sectional plane parallel with the rolling direction of the steel sheet.