To provide a method and a device for manufacturing a cylindrical device capable of obtaining a product having the consistent performance by suppressing any dispersion to be applied to an inner tube.

During the oscillation curl machining, the machining load FX1 when the displacement of an opening end 2a reaches the first predetermined quantity X1 is measured, and the subsequent machining load is determined based on the result of measurement. In a base shell 2 having high machinability, the opening end 2a is subjected to the oscillation curl machining with the relatively small machining load, and in a base shell 2 having low machinability, the opening end 2a is subjected to the oscillation curl machining with the relatively large machining load. Thus, the residual axial force to be applied to the inner tube 3 can be stabilized without being affected by the machinability of the opening end 2a of the base shell 2, in other words, the plate thickness and the caulking quantity. As a result, a product having the consistent performance can be obtained thereby.