Disclosed herein is a method and apparatus for processing natural gas composed of various hydrocarbon components for transportation of the natural gas to a demand side without separation of the hydrocarbon components, such that the natural gas can be used by consumers after being separated into the hydrocarbon components according to the needs of the demand side. The apparatus includes a storage tank; and a hydrocarbon liquefied gas mixture accommodated in the storage tank. The mixture contains hydrocarbon components composed of methane, ethane, propane and butane, and is produced by liquefying raw natural gas without changing the relative ratio of methane, ethane, propane and butane in the raw natural gas immediately after extraction from the gas well. The method and apparatus can be applied to floating marine structures.