The present invention provides a cylindrical shaft (20) formed of a bent sheet metal (10). The cylindrical shaft (20) comprises projected parts (16) projected from one end part (12) of the pair of joined end parts (12) and (14) of the sheet metal (10) and having portions which increase in width apart from the one end part (12) and recessed parts (18) formed in the other end part (14) of the pair of joined end parts, having such a shape that supplementarily matches that of the projected parts (16), and fitted to the projected parts (16). Thus, the cylindrical shaft (20) high in roundness, lessin both vertical and lateral warpages, and excellent in linearity can be provided.