A cylindrical shaft is provided of which a pair of ends are formed in a cylindrical shape by a press work so as to form a joining portion therebetween. Here, the joining portion includes: a central linear section which is provided on a center portion in an axis direction of the cylindrical shaft and is formed in a linear shape to be parallel to the axis direction of the cylindrical shaft; and a folded section which includes a plurality of intersections which are provided on both ends of the center portion and are disposed so as to be extended in a direction perpendicular to the axis direction of the cylindrical shaft, and a connection linear section which connects ends of a pair of the adjacent intersections.