A cooling device, comprising: evaporating means for storing a refrigerant; condensing means for condensing and liquefying a vapor-phase refrigerant vaporized in the evaporation means and radiating heat; a pipe connecting the evaporating means to the condensing means; and flow regulating means for regulating a flow direction of air passing through the condensing means, wherein the evaporating means and the condensing means are located on roughly the same level in the vertical direction; the evaporating means comprises an evaporation container and bulkhead means for separating the refrigerant disposed in the evaporation container; the height of the bulkhead means is larger than or equal to the height of a vapor-liquid interface of the refrigerant and is smaller than the height of the evaporation container; the pipe comprises a vapor pipe through which vapor-phase refrigerant flows and a liquid pipe through which condensed and liquefied liquid-phase refrigerant flows; characterised in that the condensing means comprises first condensing means and second condensing means which differ in condensing-means height which is defined as the height in vertical direction of a condensation container composing the condensing means, and the condensing-means height of the first condensing means is configured to be larger than the condensing-means height of the second condensing means; the first condensing means comprises a vapor pipe connection portion which is connected to the vapor pipe at the position above the condensing-means height of the second condensing means in vertical direction; and the flow regulating means is disposed in the upper part of the second condensing means. evaporating means for storing a refrigerant; condensing means for condensing and liquefying a vapor-phase refrigerant vaporized in the evaporation means and radiating heat; a pipe connecting the evaporating means to the condensing means; and flow regulating means for regulating a flow direction of air passing through the condensing means, wherein the evaporating means and the condensing means are located on roughly the same level in the vertical direction; the evaporating means comprises an evaporation container and bulkhead means for separating the refrigerant disposed in the evaporation container; the height of the bulkhead means is larger than or equal to the height of a vapor-liquid interface of the refrigerant and is smaller than the height of the evaporation container; the pipe comprises a vapor pipe through which vapor-phase refrigerant flows and a liquid pipe through which condensed and liquefied liquid-phase refrigerant flows; characterised in that the condensing means comprises first condensing means and second condensing means which differ in condensing-means height which is defined as the height in vertical direction of a condensation container composing the condensing means, and the condensing-means height of the first condensing means is configured to be larger than the condensing-means height of the second condensing means; the first condensing means comprises a vapor pipe connection portion which is connected to the vapor pipe at the position above the condensing-means height of the second condensing means in vertical direction; and the flow regulating means is disposed in the upper part of the second condensing means.