A galvanized steel sheet comprising a steel sheet having a chemical composition containing, by mass%, C: 0.05 to 0.30%, Si: 0.01 to 3.00%, Mn: 0.80 to 3.00%, Al: 0.010 to 2.000%, P: 0.100% or less, S: 0.100% or less, N: 0.0300% or less, O: 0.010% or less, B: 0 to 0.0100%, Ti: 0 to 0.100%, Nb: 0 to 0.100%, V: 0 to 0.10%, Cr: 0 to 1.00%, Ni: 0 to 0.10%, Cu: 0 to 0.10%, Mo: 0 to 0.50%, W: 0 to 0.50%, Ca: 0 to 0.100%, Mg: 0 to 0.100%, Zr: 0 to 0.100%, Hf: 0 to 0.100%, REM: 0 to 0.100% and a balance of Fe and impurities, wherein the steel sheet has a thickness of 0.10 to 0.95 mm, and a galvanized layer formed on at least one surface of the steel sheet, wherein a tensile strength is 550 to 1500 MPa, A: 1.0 μm or more, B: 10 μm or more, A/B: 0.01 to 0.50 and B/t: 0.001 to 0.200, a/A: 0.15 or less, and b/B: 0.20 or less with A being the thickness in μm of an internal oxide layer per surface of the steel sheet, B being the thickness in μm of a decarburized layer per surface of the steel sheet, t being the thickness in μm of the steel sheet, "a" being the standard deviation in μm in the width direction of a thickness of the internal oxide layer and "b" being the standard deviation in μm in the width direction of a thickness of the decarburized layer a width of the steel sheet is 1500 to 3000 mm, wherein the tensile strength, A, B and standard deviations "a" and "b" are determined as outlined in the description. a steel sheet having a chemical composition containing, by mass%, C: 0.05 to 0.30%, Si: 0.01 to 3.00%, Mn: 0.80 to 3.00%, Al: 0.010 to 2.000%, P: 0.100% or less, S: 0.100% or less, N: 0.0300% or less, O: 0.010% or less, B: 0 to 0.0100%, Ti: 0 to 0.100%, Nb: 0 to 0.100%, V: 0 to 0.10%, Cr: 0 to 1.00%, Ni: 0 to 0.10%, Cu: 0 to 0.10%, Mo: 0 to 0.50%, W: 0 to 0.50%, Ca: 0 to 0.100%, Mg: 0 to 0.100%, Zr: 0 to 0.100%, Hf: 0 to 0.100%, REM: 0 to 0.100% and a balance of Fe and impurities, wherein the steel sheet has a thickness of 0.10 to 0.95 mm, and C: 0.05 to 0.30%, Si: 0.01 to 3.00%, Mn: 0.80 to 3.00%, Al: 0.010 to 2.000%, P: 0.100% or less, S: 0.100% or less, N: 0.0300% or less, O: 0.010% or less, B: 0 to 0.0100%, Ti: 0 to 0.100%, Nb: 0 to 0.100%, V: 0 to 0.10%, Cr: 0 to 1.00%, Ni: 0 to 0.10%, Cu: 0 to 0.10%, Mo: 0 to 0.50%, W: 0 to 0.50%, Ca: 0 to 0.100%, Mg: 0 to 0.100%, Zr: 0 to 0.100%, Hf: 0 to 0.100%, REM: 0 to 0.100% and a balance of Fe and impurities, wherein the steel sheet has a thickness of 0.10 to 0.95 mm, and a galvanized layer formed on at least one surface of the steel sheet, wherein a tensile strength is 550 to 1500 MPa, A: 1.0 μm or more, B: 10 μm or more, A/B: 0.01 to 0.50 and B/t: 0.001 to 0.200, a/A: 0.15 or less, and b/B: 0.20 or less a tensile strength is 550 to 1500 MPa, A: 1.0 μm or more, B: 10 μm or more, A/B: 0.01 to 0.50 and B/t: 0.001 to 0.200, a/A: 0.15 or less, and b/B: 0.20 or less with A being the thickness in μm of an internal oxide layer per surface of the steel sheet, B being the thickness in μm of a decarburized layer per surface of the steel sheet, t being the thickness in μm of the steel sheet, "a" being the standard deviation in μm in the width direction of a thickness of the internal oxide layer and "b" being the standard deviation in μm in the width direction of a thickness of the decarburized layer a width of the steel sheet is 1500 to 3000 mm, wherein the tensile strength, A, B and standard deviations "a" and "b" are determined as outlined in the description.