An electricity storage device maintains low internal resistance and high electric capacity. The nonaqueous-electrolytic-solution hybrid electricity storage device employs an anode into/from which lithium can be intercalated and deintercalated and a cathode including activated carbon, even after high-temperature storage and/or high-temperature charging/discharging. Specifically, this electricity storage device includes an anode into/from which lithium can be intercalated and deintercalated, a cathode that includes activated carbon, and a nonaqueous electrolytic solution, wherein the electricity storage device employs a nonaqueous electrolytic solution that includes at least one type of compound represented by one of general formulas (1) to (5). Details on the general formulas (1) to (5) are as described in the Description.