A method for cooling a liquefied gas chosen from liquefied natural gas, ethane and liquefied petroleum gas contained in the interior space of a container (2, 19) by means of a vaporization device for cooling a liquefied gas; said vaporization device comprising: - a vaporization chamber arranged in the interior space of a container (2, 19) intended to be filled with liquefied gas, the vaporization chamber comprising heat exchange walls allowing an exchange of heat between an interior space of the vaporization chamber and a liquefied gas present in the interior space of the container (2, 19); - an inlet circuit comprising an intake emerging in the interior space of the container (2, 19) for withdrawing a flow of liquefied gas in liquid phase from the container (2, 19) and a head loss member emerging in the interior space of the vaporization chamber in order to expand the withdrawn gas flow; - an outlet circuit arranged to evacuate the withdrawn gas flow, in gaseous phase from the vaporization chamber to a vapor phase gas usage circuit; said outlet circuit comprising a vacuum pump configured for sucking the gas flow into the vaporization chamber, discharging it to the vapor phase gas usage circuit and maintaining an absolute pressure lower than atmospheric pressure in the vaporization chamber, the cooling method comprising: - withdrawing a flow of liquefied gas in the container (2, 19) containing a quantity of liquefied gas having to be cooled and conducting it to a vaporization chamber arranged in the interior space of the container (2, 19); - generating an absolute pressure lower than atmospheric pressure inside the vaporization chamber; - effecting a heat exchange through the walls of the vaporization chamber between the gas flow withdrawn and expanded in the vaporization chamber and the liquefied gas contained in the container (2, 19) so as to vaporize the withdrawn gas flow by absorbing calories from the liquefied gas contained in the container (2, 19); and - conducting the withdrawn gas flow in vapor phase to a vapor phase gas usage circuit. - a vaporization chamber arranged in the interior space of a container (2, 19) intended to be filled with liquefied gas, the vaporization chamber comprising heat exchange walls allowing an exchange of heat between an interior space of the vaporization chamber and a liquefied gas present in the interior space of the container (2, 19); - an inlet circuit comprising an intake emerging in the interior space of the container (2, 19) for withdrawing a flow of liquefied gas in liquid phase from the container (2, 19) and a head loss member emerging in the interior space of the vaporization chamber in order to expand the withdrawn gas flow; - an outlet circuit arranged to evacuate the withdrawn gas flow, in gaseous phase from the vaporization chamber to a vapor phase gas usage circuit; said outlet circuit comprising a vacuum pump configured for sucking the gas flow into the vaporization chamber, discharging it to the vapor phase gas usage circuit and maintaining an absolute pressure lower than atmospheric pressure in the vaporization chamber, the cooling method comprising: - withdrawing a flow of liquefied gas in the container (2, 19) containing a quantity of liquefied gas having to be cooled and conducting it to a vaporization chamber arranged in the interior space of the container (2, 19); - generating an absolute pressure lower than atmospheric pressure inside the vaporization chamber; - effecting a heat exchange through the walls of the vaporization chamber between the gas flow withdrawn and expanded in the vaporization chamber and the liquefied gas contained in the container (2, 19) so as to vaporize the withdrawn gas flow by absorbing calories from the liquefied gas contained in the container (2, 19); and - conducting the withdrawn gas flow in vapor phase to a vapor phase gas usage circuit. - withdrawing a flow of liquefied gas in the container (2, 19) containing a quantity of liquefied gas having to be cooled and conducting it to a vaporization chamber arranged in the interior space of the container (2, 19); - generating an absolute pressure lower than atmospheric pressure inside the vaporization chamber; - effecting a heat exchange through the walls of the vaporization chamber between the gas flow withdrawn and expanded in the vaporization chamber and the liquefied gas contained in the container (2, 19) so as to vaporize the withdrawn gas flow by absorbing calories from the liquefied gas contained in the container (2, 19); and - conducting the withdrawn gas flow in vapor phase to a vapor phase gas usage circuit.