a base steel sheet;

a silicon-containing oxide layer provided on the base steel sheet;

an iron-based oxide layer provided on the silicon-containing oxide layer; and

a tension-insulation coating provided on the iron-based oxide layer, having a thickness of 1 to 3 μm, and containing phosphate and colloidal silica as main components,

wherein the base steel sheet contains, in terms of mass %, 2.5 to 4.5% of Si, 0.05 to 1.00% of Mn, 0% or more and less than 0.05% of Al, 0% or more and less than 0.1% of C, 0% or more and less than 0.05% of N, 0% or more and less than 0.1% of S, 0% or more and less than 0.05% of Se, 0% or more and less than 0.01% of Bi, and the remainder: Fe and impurities as chemical components, and

when the tension-insulation coating undergoes elemental analysis using a glow discharge optical emission spectrometry in a sheet thickness direction from a surface of the tension- insulation coating,

(a) there are two or more peaks of a Si emission intensity;

(b) a peak A which is a peak of the Si emission intensity existing furthest to the base steel sheet side in the sheet thickness direction exists between an inflection point at which a rate of increase in an Fe emission intensity in the sheet thickness direction from the surface of the tension-insulation coating changes and a saturation point at which the Fe emission intensity become saturated; and

(c) when a length of a perpendicular line when a perpendicular line is drawn from the top portion of a peak to a baseline connecting valley portions closest to the peak is defined as a peak height, a peak height of the peak A is 0.30 times or more and 2.5 times or less the Si emission intensity in the base steel sheet.