To provide a manufacturing method for a transmission belt, which enables a material for a pile of a pile-implanted layer to be easily changed even if the type of the belt is changed, and which enables the transmission belt to be molded in a short time.

After the formation of the pile-implanted layer 26 on a base material 56, the pile-implanted layer 26 separated from the base material 56 is wound around a rubber sleeve 24 for the manufacture of the rubber sleeve 24 with the pile-implanted layer. The rubber sleeve 24 with the pile-implanted layer is arranged between an inner mold 41 which is fitted with a flexible jacket 42, and an outer mold 46 which has a mold portion 45 engraved in the inner peripheral surface; a pre-molding body 21 is manufactured in such a manner that the flexible jacket 42 is expanded so that the rubber sleeve 24 can adhere to the engraved mold portion 45 of the outer mold; another sleeve 25 is manufactured in such a manner that at least a core wire is wound around the surface of the flexible jacket 42 of the inner mold separated from the outer mold 46; the inner mold 41 is installed in the outer mold 46; and a belt sleeve is manufactured by expanding the flexible jacket 42 and vulcanizing another sleeve 25 integrally with the pre-molding 21.