NOVELTY - An electric storage device (10) comprises a positive electrode system, and a negative electrode system including a first negative-electrode mixture layer (20) and a second negative-electrode mixture layer (22). The first and the second negative-electrode mixture layers have different material or material composition ratios, and charge/discharge characteristics. A through-hole (16a) is formed on current collector arranged between the first and second negative-electrode mixture layer.    USE - As an electric storage device that is mounted to e.g. electrical vehicle, and hybrid vehicle; and as an hybrid capacitor.    ADVANTAGE - Since the negative electrodes, each having a different charge/discharge characteristic, are provided, an energy density and an output density of the electric storage device can be enhanced. Ions can move between the negative-electrode mixture layers via the through-holes, thus a variation in the potential of the negative electrodes can be canceled, even in case where the negative electrodes, each having a different charge/discharge characteristic are combined. Therefore, the durability of the electric storage device can be secured.    DETAILED DESCRIPTION - An electric storage device (10) comprises a positive electrode system including a positive electrode (13) having a current collector (16) and a positive-electrode mixture layer (17), and a negative electrode system including a negative electrode (14) having a current collector and a negative-electrode mixture layer. The negative electrode system includes a first negative-electrode mixture layer (20) and a second negative-electrode mixture layer (22), which are connected to each other and which include at least one different material or have different material composition ratios. The first negative-electrode mixture layer and the second negative-electrode mixture layer have different charge/discharge characteristics. A through-hole (16a) is formed on the current collector arranged between the first and the second negative-electrode mixture layers. The first and the second negative-electrode mixture layers are electrically connected to each other for moving ions between the first and the second layers via the through-hole. The first and the second layers includes an active material differ from each other. The first and second negative electrodes sandwich the positive electrode, where the through-hole is formed on the current collector of the positive electrode arranged between negative-electrode mixture layers of first electrode and second negative electrode. The electric storage device further comprises a lithium ion source that is short-circuited to at least either one of the negative electrode and the positive electrode, where lithium ions are doped from the lithium ion source into at least either one of the negative electrode and the positive electrode. The device structure is a laminate type in which the positive electrode and the negative electrode are alternately laminated, or a wound type in which the positive electrode and the negative electrode are laminated and wound. The positive-electrode mixture layer contains an active carbon.    DESCRIPTION OF DRAWING(S) - The figure shows a sectional view of an internal structure of the electrical storage device.    Electric storage device (10)    Positive electrode (13)    Negative electrode (14)    current collector of positive electrode (16)    Through-hole (16a)    First negative-electrode mixture layer (20)    Second negative-electrode mixture layer (22)