PRODUCTION METHOD FOR FORGED CRANKSHAFT

A production method includes a preforming process, a forming process and a finish forging process. In the preforming process, an intermediate preform (24) is formed from a billet. In the forming process, while each of a plurality of rough journals (24j) of the intermediate preform is held and pressed vertically by a pair of holding dies (60), rough pins (24p) are decentered in directions perpendicular to the pressing direction by the holding dies (60) and an axial direction of the intermediate preform (24), and the intermediate preform (24) is pressed in the axial direction of the intermediate preform (24). In the finish forging process, a final preform (25) is placed such that the directions in which the rough pins (24p) are decentered are parallel to a horizontal direction, and the thus placed final preform (25) is pressed vertically by a pair of pressing dies, whereby a finish-forged product (26) including a plurality of journals (J), a plurality of pins (P) and a plurality of crankarms (A) is formed. The production method reduces the risk of occurrence of seams on a forged crankshaft.