To provide a winding core, capable of imparting a stepped flaw onto a sheet, in which a step is not generated when the sheet is started to be wound on a winding core; and a manufacturing method therefor.

In the winding core, a recessed line is formed in a length direction of an outer surface of a cylindrical body. A shape of cross section of the recessed line comprises a vertical surface in an approximate diameter direction of the cylindrical body; and a circular surface being approximately the same circle to the outer surface of the cylindrical body.