A steel sheet which is a cold-rolled steel sheet, the steel sheet comprising, as a chemical composition, by mass%, C: 0.01% to 0.4%, Si: 0.001% to 2.5%, Mn: 0.001% to 4.0%, Al: 0.001% to 2.0%, P: limited to 0.15% or less, S: limited to 0.03% or less, N: limited to 0.01% or less, O: limited to 0.01% or less, optionally, at least one selected from the group consisting of Ti: 0.001% to 0.2%, Nb: 0.001% to 0.2%, B: 0.0001% to 0.005%, Mg: 0.0001% to 0.01%, Rare Earth Metal: 0.0001% to 0.1%, Ca: 0.0001% to 0.01%, Mo: 0.001% to 1.0%, Cr: 0.001% to 2.0%, V: 0.001% to 1.0%, Ni: 0.001% to 2.0%, Cu: 0.001% to 2.0%, Zr: 0.0001% to 0.2%, W: 0.001% to 1.0%, As: 0.0001% to 0.5%, Co: 0.0001% to 1.0%, Sn: 0.0001% to 0.2%, Pb: 0.0001% to 0.2%, Y: 0.001% to 0.2%, and Hf: 0.001% to 0.2%, and a balance consisting of Fe and unavoidable impurities, wherein: an average pole density of an orientation group of <011> to <110>, which is a pole density represented by an arithmetic average of pole densities of each crystal orientation <011>, <110>, <110>, <110>, and <110>, is 1.0 to 5.0 and a pole density of a crystal orientation <113> is 1.0 to 4.0 in a thickness central portion which is a thickness range of 5/8 to 3/8 based on a surface of the steel sheet; a Lankford-value rC in a direction perpendicular to a rolling direction is 0.70 to 1.50 and a Lankford-value r30 in a direction making an angle of 30° with the rolling direction is 0.70 to 1.50; the steel sheet includes, as a metallographic structure, plural grains, the metallographic structure of the steel sheet consists of a martensite, at least one selected from a ferrite and a bainite, and a balance; the amount of the martensite being 1% to 70%, the total amount of the ferrite and the bainite being 30% to 99%, and the amount of the balance being limited to 0% to 10%; when an area fraction of the martensite is defined as fM in unit of area%, an average size of the martensite is defined as dia in unit of μm, an average distance between the martensite is defined as dis in unit of μm, and a tensile strength of the steel sheet is defined as TS in unit of MPa, the following Expression 1 and the following Expression 2 are satisfied; when a major axis of the martensite is defined as La and a minor axis of the martensite is defined as Lb, an area fraction of the martensite satisfying the following Expression 3 is 50% to 100% as compared with the area fraction fM of the martensite; the tensile strength of the steel sheet is 440 MPa or more, dia ≤ 13 μm TS / fM × dis / dia ≥ 500 La / Lb ≤ 5.0 C: 0.01% to 0.4%, Si: 0.001% to 2.5%, Mn: 0.001% to 4.0%, Al: 0.001% to 2.0%, P: limited to 0.15% or less, S: limited to 0.03% or less, N: limited to 0.01% or less, O: limited to 0.01% or less, optionally, at least one selected from the group consisting of Ti: 0.001% to 0.2%, Nb: 0.001% to 0.2%, B: 0.0001% to 0.005%, Mg: 0.0001% to 0.01%, Rare Earth Metal: 0.0001% to 0.1%, Ca: 0.0001% to 0.01%, Mo: 0.001% to 1.0%, Cr: 0.001% to 2.0%, V: 0.001% to 1.0%, Ni: 0.001% to 2.0%, Cu: 0.001% to 2.0%, Zr: 0.0001% to 0.2%, W: 0.001% to 1.0%, As: 0.0001% to 0.5%, Co: 0.0001% to 1.0%, Sn: 0.0001% to 0.2%, Pb: 0.0001% to 0.2%, Y: 0.001% to 0.2%, and Hf: 0.001% to 0.2%, and a balance consisting of Fe and unavoidable impurities, wherein: an average pole density of an orientation group of <011> to <110>, which is a pole density represented by an arithmetic average of pole densities of each crystal orientation <011>, <110>, <110>, <110>, and <110>, is 1.0 to 5.0 and a pole density of a crystal orientation <113> is 1.0 to 4.0 in a thickness central portion which is a thickness range of 5/8 to 3/8 based on a surface of the steel sheet; a Lankford-value rC in a direction perpendicular to a rolling direction is 0.70 to 1.50 and a Lankford-value r30 in a direction making an angle of 30° with the rolling direction is 0.70 to 1.50; the steel sheet includes, as a metallographic structure, plural grains, the metallographic structure of the steel sheet consists of a martensite, at least one selected from a ferrite and a bainite, and a balance; the amount of the martensite being 1% to 70%, the total amount of the ferrite and the bainite being 30% to 99%, and the amount of the balance being limited to 0% to 10%; when an area fraction of the martensite is defined as fM in unit of area%, an average size of the martensite is defined as dia in unit of μm, an average distance between the martensite is defined as dis in unit of μm, and a tensile strength of the steel sheet is defined as TS in unit of MPa, the following Expression 1 and the following Expression 2 are satisfied; when a major axis of the martensite is defined as La and a minor axis of the martensite is defined as Lb, an area fraction of the martensite satisfying the following Expression 3 is 50% to 100% as compared with the area fraction fM of the martensite; the tensile strength of the steel sheet is 440 MPa or more, dia ≤ 13 μm TS / fM × dis / dia ≥ 500 La / Lb ≤ 5.0