This wound core is a wound core including: a substantially rectangular wound core main body in a side view in which first planar portions and corner portions are alternately continuous and at least one of two or more bent portions existing in at least one corner portion satisfies Equations (1) to (3) below.
Tave40 nm(1)
(ToTu)/Tave0.50(2)
Tave(ToTu)240 nm.sup.2(3)

A manufacturing method of a grain-oriented electrical steel sheet according to an embodiment of the present invention includes producing a cold-rolled plate; forming a groove in the cold-rolled plate; performing primary recrystallization annealing to the cold-rolled plate; and applying an annealing separator to the primary-recrystallized cold-rolled plate and performing secondary recrystallization annealing, wherein a weight ratio of SiO.sub.2/Fe.sub.xSiO.sub.y of the surface layer part of the cold-rolled plate is 0.3 to 3 after the primary recrystallization annealing of the cold-rolled plate. (Here, x is an integer from 1 to 2, and y is an integer from 2 to 4.)

In this method of producing a wound core, at least one bent portion (5) of one or more laminated grain oriented electrical steel sheets (1) is formed such that one side (1b) of the steel sheet (1) is placed and constrained on a die (30) and a punch (40) is press formed against a portion (1a) of the steel sheet (1) to be bent on the other free end side in the thickness (T) direction of the steel sheet. Outer surfaces of the die and the punch each have an arc portion (30a, 40a) having a predetermined curvature, and when the thickness of the steel sheet (1) is T, bent angles of the bent portions (5) are (), a radius of curvature of the arc portion (30a) of the die is Rd, and a radius of curvature of the arc portion (40a) of the punch is Rp, relationships of Equations (1) to (5) below are satisfied. $\begin{array}{cc}0.02T/\left(2\mathrm{Rd}+T\right)0.15& \left(1\right)\end{array}$$\begin{array}{cc}0.5\mathrm{Rd}3.& \left(2\right)\end{array}$$\begin{array}{cc}0.15T0\text{.30}& \left(3\right)\end{array}$$\begin{array}{cc}2.5\mathrm{Rp}/\mathrm{Rd}10& \left(4\right)\end{array}$$\begin{array}{c}10\end{array}$