A liquefied gas disposal system, comprising: a compression means for compressing ambient air; a pressurized combustion means including: a furnace into which ambient air compressed by the compression means is led as jacket air and combustion air and in which vaporized liquefied gas led out from a storage vessel combusts with the combustion air, and a jacket part which covers a surrounding of a furnace wall constituting the furnace and into which the jacket air is led; an opening control valve which is provided near an inlet of the furnace and adjusts the pressure of the combustion air so that the pressure of the combustion air supplied to the furnace is lower than the pressure of the jacket air supplied to the furnace; a high-pressure-side steam generation means (7, 8) for generating steam through heat exchange with the flue gas which is led out from the pressurized combustion means; a steam turbine to which the steam generated in the high-pressure-side steam generation means (7, 8) is led; a gas turbine which is provided on a common shaft with the air compression means, and is rotated by the flue gas led from the high-pressure-side steam generation means (7, 8); and an electric motor/generator which is driven by the gas turbine, wherein the electric motor/generator serves as a power generator to generate power when the gas turbine is driven, and serves as an electric motor by being reversely supplied with power when activating the liquefied gas disposal system, to rotationally drive the compression means. a compression means for compressing ambient air; a pressurized combustion means including: a furnace into which ambient air compressed by the compression means is led as jacket air and combustion air and in which vaporized liquefied gas led out from a storage vessel combusts with the combustion air, and a jacket part which covers a surrounding of a furnace wall constituting the furnace and into which the jacket air is led; a furnace into which ambient air compressed by the compression means is led as jacket air and combustion air and in which vaporized liquefied gas led out from a storage vessel combusts with the combustion air, and a jacket part which covers a surrounding of a furnace wall constituting the furnace and into which the jacket air is led; an opening control valve which is provided near an inlet of the furnace and adjusts the pressure of the combustion air so that the pressure of the combustion air supplied to the furnace is lower than the pressure of the jacket air supplied to the furnace; a high-pressure-side steam generation means (7, 8) for generating steam through heat exchange with the flue gas which is led out from the pressurized combustion means; a steam turbine to which the steam generated in the high-pressure-side steam generation means (7, 8) is led; a gas turbine which is provided on a common shaft with the air compression means, and is rotated by the flue gas led from the high-pressure-side steam generation means (7, 8); and an electric motor/generator which is driven by the gas turbine, wherein the electric motor/generator serves as a power generator to generate power when the gas turbine is driven, and serves as an electric motor by being reversely supplied with power when activating the liquefied gas disposal system, to rotationally drive the compression means.