NOVELTY - The electrode (2) has binder e.g. anionic material and vinylidene fluoride, containing anionic material e.g. polyacrylic acid, and conductive assistant, where a ratio of a polyaniline oxidized body in the electrode is 0.01 to 75% to entire polyaniline i.e. polyaniline derivative. The electrode is formed by using a positive electrode forming material such as active material particles containing polyaniline, where the polyaniline refers to polymer obtained by subjecting aniline to electrolytic polymerization or chemical oxidation polymerization.    USE - Positive electrode for a power storage device (claimed) i.e. lithium secondary battery, used for a portable electronic device e.g. portable personal computer, mobile phone and personal digital assistant (PDA), and driving power supplies for hybrid electric vehicles, electric vehicles and fuel cell vehicles.    ADVANTAGE - The electrode has an excellent discharge characteristic irrespective of an oxidized state of polyaniline as positive active material such that power storage device can ensure excellent storability and handleability. The ratio of the polyaniline oxidized body is controlled to be low such that power storage device capable of being fully charged from the initial time and excellent in charge-discharge cycle stability can be obtained.    DETAILED DESCRIPTION - The aniline is selected from a group consisting of o-substituted anilines such as o-methylaniline, o-ethylaniline, o-phenylaniline, o-methoxyaniline and o-ethoxyaniline, and m-substituted anilines such as m-methylaniline, m-ethylaniline, m-methoxyaniline, m-ethoxyaniline and m-phenylaniline. The conductive assistant is one of conductive carbon material, metal material, conductive carbon black such as acetylene black and Ketjen black, and fibrous carbon material such as carbon fiber and carbon nanotube. An INDEPENDENT CLAIM is also included for a power storage device.    DESCRIPTION OF DRAWING(S) - The drawing shows a schematic sectional view of a power storage device.    Positive electrode current collector (1)    Positive electrode (2)    Electrolyte layer (3)    Negative electrode (4)    Negative electrode current collector (5)