A forging method for a shaft member of a constant velocity universal joint comprising a plurality of enlarged diameter portions (61, 62) on a shaft section of the shaft member, the forging method comprising: preforming at least one of the plurality of enlarged diameter portions (61, 62) to obtain a semi-finished member (B"), wherein the preformed at least one of the plurality of enlarged diameter portions (61, 62) is an enlarged diameter portion on a joining side, in which a large diameter portion and a recessed portion are formed; and forming a remainder of the enlarged diameter portions (61, 62) in the semi-finished member (B") using a mold, the mold comprising: a punch; split dies, which are configured to accommodate the at least one of the enlarged diameter portions (61, 62) and the shaft section of the semi-finished member (B") therein, and each comprise a forming surface; and a workpiece receiving member, which is configured to allow the at least one of the enlarged diameter portions (61, 62) of the semi-finished member (B") to be placed thereon, and receive pressure applied by the punch, the forming a remainder of the enlarged diameter portions (61, 62) comprising: allowing the semi-finished member (B") having the at least one of the enlarged diameter portions (61, 62) to be placed on the workpiece receiving member; cramping the semi-finished member (B") with an extremely small gap in a radial direction of the semi-finished member (B") by closing the split dies, so that the semi-finished member (B") is movable in an axial direction with respect to the split dies; and filling the semi-finished member (B") into the forming surfaces of the split dies by the pressure applied by the punch under the state in which the semi-finished member (B") is cramped, and during filling, a retreat amount of the workpiece receiving member is regulated by a stopper. preforming at least one of the plurality of enlarged diameter portions (61, 62) to obtain a semi-finished member (B"), wherein the preformed at least one of the plurality of enlarged diameter portions (61, 62) is an enlarged diameter portion on a joining side, in which a large diameter portion and a recessed portion are formed; and forming a remainder of the enlarged diameter portions (61, 62) in the semi-finished member (B") using a mold, the mold comprising: a punch; split dies, which are configured to accommodate the at least one of the enlarged diameter portions (61, 62) and the shaft section of the semi-finished member (B") therein, and each comprise a forming surface; and a workpiece receiving member, which is configured to allow the at least one of the enlarged diameter portions (61, 62) of the semi-finished member (B") to be placed thereon, and receive pressure applied by the punch, a punch; split dies, which are configured to accommodate the at least one of the enlarged diameter portions (61, 62) and the shaft section of the semi-finished member (B") therein, and each comprise a forming surface; and a workpiece receiving member, which is configured to allow the at least one of the enlarged diameter portions (61, 62) of the semi-finished member (B") to be placed thereon, and receive pressure applied by the punch, the forming a remainder of the enlarged diameter portions (61, 62) comprising: allowing the semi-finished member (B") having the at least one of the enlarged diameter portions (61, 62) to be placed on the workpiece receiving member; cramping the semi-finished member (B") with an extremely small gap in a radial direction of the semi-finished member (B") by closing the split dies, so that the semi-finished member (B") is movable in an axial direction with respect to the split dies; and filling the semi-finished member (B") into the forming surfaces of the split dies by the pressure applied by the punch under the state in which the semi-finished member (B") is cramped, and during filling, a retreat amount of the workpiece receiving member is regulated by a stopper. allowing the semi-finished member (B") having the at least one of the enlarged diameter portions (61, 62) to be placed on the workpiece receiving member; cramping the semi-finished member (B") with an extremely small gap in a radial direction of the semi-finished member (B") by closing the split dies, so that the semi-finished member (B") is movable in an axial direction with respect to the split dies; and filling the semi-finished member (B") into the forming surfaces of the split dies by the pressure applied by the punch under the state in which the semi-finished member (B") is cramped, and during filling, a retreat amount of the workpiece receiving member is regulated by a stopper.