A high-strength galvanized steel sheet having a tensile strength of 1000 MPa or more measured according to the method mentioned in the description, comprising: a base steel sheet having a composition containing, by mass, C: 0.05% to 0.30%, Si: 3.0% or less, Mn: 1.5% to 4.0%, P: 0.100% or less, S: 0.02% or less, and Al: 1.0% or less, optionally one or more elements selected from Cr: 0.005% to 2.0%, Mo: 0.005% to 2.0%, V: 0.005% to 2.0%, Ni: 0.005% to 2.0%, Cu: 0.005% to 2.0%, Nb: 0.005% to 0.20%, Ti: 0.005% to 0.20%, B: 0.0001% to 0.0050%, Ca: 0.0001% to 0.0050%, REM: 0.0001% to 0.0050%, Sb: 0.0010% to 0.10%, and Sn: 0.0010% to 0.50%, with the balance being Fe and inevitable impurities wherein the inevitable impurities include Zr, Mg, La and Ce at a content of 0.002% or less in total, and N at a content of 0.008% or less, the base steel sheet having a microstructure including ferrite and carbide-free bainite, martensite and carbide-containing bainite, and retained austenite, the total area fraction of ferrite and carbide-free bainite being 0% to 65%, the total area fraction of martensite and carbide-containing bainite being 35% to 100%, the area fraction of retained austenite being 0% to 15%, and the area fraction of phases other than the above phases is 10% or less wherein the area fraction of the retained austenite is determined according to the method disclosed in the description, wherein carbide-free bainite refers to bainite in which the presence of carbide particles is not confirmed in an image captured by the method specified in the description and carbide-containing bainite refers to bainite in which the presence of carbide particles is confirmed in an image captured by the method specified in the description, the content of diffusible hydrogen in the base steel sheet being 0.00008% by mass or less, including 0%, measured by the method specified in the description; and a galvanizing layer disposed on the base steel sheet, wherein the density of gaps in the galvanizing layer, the gaps cutting across the entire thickness of the galvanizing layer in a cross section of the steel sheet, the cross section being taken in a thickness direction of the steel sheet so as to be perpendicular to a rolling direction of the steel sheet, is 10 gaps/mm or more. a base steel sheet having a composition containing, by mass, C: 0.05% to 0.30%, Si: 3.0% or less, Mn: 1.5% to 4.0%, P: 0.100% or less, S: 0.02% or less, and Al: 1.0% or less, C: 0.05% to 0.30%, Si: 3.0% or less, Mn: 1.5% to 4.0%, P: 0.100% or less, S: 0.02% or less, and Al: 1.0% or less, optionally one or more elements selected from Cr: 0.005% to 2.0%, Mo: 0.005% to 2.0%, V: 0.005% to 2.0%, Ni: 0.005% to 2.0%, Cu: 0.005% to 2.0%, Nb: 0.005% to 0.20%, Ti: 0.005% to 0.20%, B: 0.0001% to 0.0050%, Ca: 0.0001% to 0.0050%, REM: 0.0001% to 0.0050%, Sb: 0.0010% to 0.10%, and Sn: 0.0010% to 0.50%, Cr: 0.005% to 2.0%, Mo: 0.005% to 2.0%, V: 0.005% to 2.0%, Ni: 0.005% to 2.0%, Cu: 0.005% to 2.0%, Nb: 0.005% to 0.20%, Ti: 0.005% to 0.20%, B: 0.0001% to 0.0050%, Ca: 0.0001% to 0.0050%, REM: 0.0001% to 0.0050%, Sb: 0.0010% to 0.10%, and Sn: 0.0010% to 0.50%, with the balance being Fe and inevitable impurities wherein the inevitable impurities include Zr, Mg, La and Ce at a content of 0.002% or less in total, and N at a content of 0.008% or less, the base steel sheet having a microstructure including ferrite and carbide-free bainite, martensite and carbide-containing bainite, and retained austenite, the total area fraction of ferrite and carbide-free bainite being 0% to 65%, the total area fraction of martensite and carbide-containing bainite being 35% to 100%, the area fraction of retained austenite being 0% to 15%, and the area fraction of phases other than the above phases is 10% or less wherein the area fraction of the retained austenite is determined according to the method disclosed in the description, wherein carbide-free bainite refers to bainite in which the presence of carbide particles is not confirmed in an image captured by the method specified in the description and carbide-containing bainite refers to bainite in which the presence of carbide particles is confirmed in an image captured by the method specified in the description, the content of diffusible hydrogen in the base steel sheet being 0.00008% by mass or less, including 0%, measured by the method specified in the description; and a galvanizing layer disposed on the base steel sheet, wherein the density of gaps in the galvanizing layer, the gaps cutting across the entire thickness of the galvanizing layer in a cross section of the steel sheet, the cross section being taken in a thickness direction of the steel sheet so as to be perpendicular to a rolling direction of the steel sheet, is 10 gaps/mm or more.