To prevent overcooling without decreasing cooling performance or increasing the size of a product, concerning a cooling device and a heating element storage apparatus using the same.

The cooling device includes natural-circulation-system loop thermosiphons (10a, 10b) formed by circularly connecting evaporators (8a, 8b) and condensers (9a, 9b) with a refrigerant pipe. The device includes: a first inlet (inside-air inlet 16) and a first outlet (inside-air outlet 17) for ventilation to the evaporators (8a, 8b); and a second inlet (outside-air inlet 18) and a second outlet (outside-air outlet 19) for ventilation to the condensers (9a, 9b). The device further includes a partition member (partition plate 13) for separating an evaporator-side passage 14 from a condenser-side passage 15 between an evaporator cover 11 and a condenser cover 12. One or more bent parts are provided between the outside-air inlet 18 and the outside-air outlet 19 to prevent outside air from excessively flowing to the condensers.