A manufacturing method of a Z straddled vehicle Z body frame including: fabricating a plurality of main frame members that are commonly usable in a plurality of types of straddled vehicles; and forming a pivot hole to which a pivot shaft Z that supports a swing arm, is attachable in each main frame member, said pivot shaft is configured to be attached with an axial direction of the pivot shaft extending in a vehicle left-and-right direction, wherein each main frame member includes a hole formable portion in which the pivot hole is formable and which has an area larger than that of a head portion of the pivot shaft when viewed in axial direction of the pivot shaft, and a rotation restricting portion that restricts rotation of the head portion of the pivot shaft inserted into the pivot hole, the forming of the pivot hole in each main frame member includes forming the pivot hole at a predetermined position in accordance with a type of a straddled vehicle in the hole formable portion of each main frame member, and positions of a plurality of pivot holes that are predetermined in accordance with the types of the straddled vehicles in the plurality of main frame members are different from one another, wherein the head portion of the pivot shaft has an oblong shape, the rotation restricting portion is formed such that the head portion of the pivot shaft is fittable into the rotation restricting portion, and is formed to extend in a first direction, a length in the first direction of the rotation restricting portion is larger than a maximum dimension of the head portion of the pivot shaft, and a length in a second direction that is orthogonal to the first direction of the rotation restricting portion is smaller than the maximum dimension of the head portion of the pivot shaft. fabricating a plurality of main frame members that are commonly usable in a plurality of types of straddled vehicles; and forming a pivot hole to which a pivot shaft Z that supports a swing arm, is attachable in each main frame member, said pivot shaft is configured to be attached with an axial direction of the pivot shaft extending in a vehicle left-and-right direction, wherein each main frame member includes a hole formable portion in which the pivot hole is formable and which has an area larger than that of a head portion of the pivot shaft when viewed in axial direction of the pivot shaft, and a rotation restricting portion that restricts rotation of the head portion of the pivot shaft inserted into the pivot hole, the forming of the pivot hole in each main frame member includes forming the pivot hole at a predetermined position in accordance with a type of a straddled vehicle in the hole formable portion of each main frame member, and positions of a plurality of pivot holes that are predetermined in accordance with the types of the straddled vehicles in the plurality of main frame members are different from one another, wherein the head portion of the pivot shaft has an oblong shape, the rotation restricting portion is formed such that the head portion of the pivot shaft is fittable into the rotation restricting portion, and is formed to extend in a first direction, a length in the first direction of the rotation restricting portion is larger than a maximum dimension of the head portion of the pivot shaft, and a length in a second direction that is orthogonal to the first direction of the rotation restricting portion is smaller than the maximum dimension of the head portion of the pivot shaft.