In this wound core, the average distance of first-group joint portions and the average distance of second-group joint portions determined under predetermined conditions satisfy predetermined conditions.

A wound core in which the average distance of first-group joint portions and the average distance of second-group joint portions determined under predetermined conditions are 25 mm or more.

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.)