A lithium ion capacitor having high energy density, high output density, high capacity and high safety is provided.A lithium ion capacitor comprising a positive electrode 1 made of a material capable of being reversibly doped with lithium ions and/or anions, a negative electrode 2 made of a material capable of being reversively doped with lithium ions, and an aprotic organic solution of a lithium salt as an electrolytic solution, wherein the positive electrode 1 and the negative electrode 2 are laminated or wound with a separator interposed between them, the area of the positive electrode 1 is smaller than the area of the negative electrode 2, and the face of the positive electrode 1 is substantially covered by the face of the negative electrode 2 when they are laminated or wound.