To provide a method of winding of core wire for transmission belt and an apparatus therefor in which appearance defectiveness by wrinkles of the transmission belt can be eliminated by removing swelling of a sheet body appearing near front of a core wire installation portion susceptible to occur, when the core wire having a specified tensile force is wound spirally around the sheet body in which an extension layer and an adhesion layer are laminated on a canvas by which a metallic mold is covered at a forming step of the transmission belt.

The method comprises the step in which the swelling part F produced at the end portion of the winding part is dislodged toward the open end by compressing firmly with a pressing roll 15 and then released when winding the core wire C spirally around a tube-shaped sheet body S which covers the metallic mold K, wherein the simple and easy apparatus is used for releasing the swelling by shuttle operation of the pressing roll 15 without manual actuation with shuttle speed being altered by detecting the diameter of mold even when the diameters of the metallic mold are differed.