Manufacturing method of a cylindrical electric double layer capacitor

A cylindrical electric double-layer capacitor includes a cylindrical sealed vessel housing an electrode roll and an electrolyte solution. The electrode roll is formed of a rolled superposed assembly having band-shaped positive and negative poles and two band-shaped separators sandwiching one of the band-shaped positive and negative poles. Each of the band-shaped positive and negative poles includes a band-shaped collector and a pair of polarizing electrodes formed in a laminated manner on opposite surfaces of the band-shaped collector. In a state in which the electrode roll has been accommodated in the sealed vessel along with the electrolyte solution, an outer diameter D1 of the electrode roll and an inner diameter D2 of the sealed vessel are brought into a relationship of D1=D2 by at least one of swelling of the polarizing electrodes caused by the electrolyte solution and expansion of the polarizing electrodes caused by an electrical charge. Thus, in the cylindrical electric double-layer capacitor, it is possible to avoid an increase in internal resistance, a reduction in a self-discharging characteristic and other like electrical characteristics.