To manufacture a cylindrical shaft 20 having high roundness over its whole length by bending work.

In a method for manufacturing the cylindrical shaft 20, a metal sheet 10 is worked into such a shape that each of cross-sectional shapes orthogonal to a longitudinal direction is circular, by press-molding it in the width direction. The method includes: a preliminary step of bending a portion of ≥50% in width of the metal sheet 10 into a circular-arc shape; a pre-finish step of working the sheet metal to the stage where the diameter of the metal sheet 10 of the cross section orthogonal to the longitudinal direction, which diameter is parallel to the mating direction of the dies 50, is shorter than the finish diameter of a shaft product, and where the diameter of the metal sheet 10, which diameter is orthogonal to the mating direction of the dies 50, is longer than the finish diameter of the shaft product by using a pair of dies 50, which approach each other and form the metal sheet 10 fed from the preliminary step into a cylindrical shape; and a finish step of finishing the working at the state that the inner surface of the groove is in contact with the surface of the metal sheet 10, by using a pair of dies 60 having grooves, whose inner surfaces have the shapes of a semi-circle having the same inner diameter as the finish diameter of the shaft product, which extend in the longitudinal direction, and which are used as working surfaces.

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