A cold storage device includes a rechargeable battery set disposed in an inner receiving space in a case body, a thermoelectric cooling unit mounted in the case body and connected electrically to the rechargeable battery set for cooling a cold storage space in the case body, a charging mode selecting unit operable so as to select one of electrical energy converted from solar power by a solar power collecting plate, DC power from an external DC power source, and DC power obtained by converting AC power from an external AC power source to charge the rechargeable battery set, and a power output selecting unit operable so as to output one of the electrical power from the rechargeable battery set and AC power obtained by converting the electrical power from the rechargeable battery set at a corresponding one of AC and DC output ports.