Capacitor

A method of preventing oxidation-induced deterioration of a sealing member in a capacitor including:

• a capacitor element holding a predetermined solution between an anode foil and a cathode foil that are wound up with a separator in between;
• a body case for housing the capacitor element;
• and
• the sealing member for sealing the body case,
• wherein
• the solution contains, dissolved in a lipophilic solvent, a sealing member deterioration preventing agent that solidifies by oxidation, the solution being supplied through the separator to the sealing member, and
• the sealing member deterioration preventing agent permeates the sealing member and reaches an outer face of the sealing member to form on the outer face of the sealing member a coating resulting from the sealing member deterioration preventing agent solidifying, thereby preventing oxidation-induced deterioration of the sealing member.