A lithium ion capacitor including a positive electrode, a negative
electrode, and an aprotic organic solvent solution of a lithium salt as
an electrolytic solution. The positive electrode active material is
capable of reversibly supporting lithium ions and/or anions, the negative
electrode active material is capable of reversibly supporting lithium
ions and anions, and the potentials of the positive electrode and the
negative electrode are at most 2.0 V after the positive electrode and the
negative electrode are short-circuited. The positive electrode and the
negative electrode are alternately laminated with a separator interposed
therebetween to constitute an electrode unit, the cell is constituted by
at least two such electrode units, lithium metal is disposed between the
electrode units, and lithium ions are preliminarily supported by the
negative electrode and/or the positive electrode by electrochemical
contact of the lithium metal with the negative electrode and/or the
positive electrode.