A system for producing gasoline from natural gas via methanol, comprising: a steam-reforming device for generating reformed gas by steam-reforming natural gas; a methanol synthesis device for synthesizing methanol from the reformed gas; a first gasoline synthesis column (30, 30A) for synthesizing gasoline from the methanol, comprising: reaction tubes for synthesizing gasoline from methanol, wherein two types of catalysts including a dimethyl ether synthesis catalyst for synthesizing dimethyl ether from methanol and a gasoline synthesis catalyst for synthesizing gasoline from dimethyl ether are charged inside the reaction tube in two stages; and a duct which allows combustion air to flow outside the reaction tubes, wherein the duct is configured so that heat exchange is carried out between synthesis heat generated in the reaction tubes and the combustion air that flows through the duct, wherein the duct is configured so as to allow the combustion air to flow outside a portion of the reaction tubes in which the dimethyl ether synthesis catalyst is charged and then to flow outside a portion of the reaction tubes in which the gasoline synthesis catalyst is charged; a fan for feeding combustion air; a steam-combustion air heat exchanger configured to preheat the combustion air with steam; a flue gas-combustion air heat exchanger which is configured to preheat combustion air with flue gas that flows in a waste heat recovery portion of the steam-reforming device; a combustion air introduction line which is configured to introduce the preheated combustion air into the duct; and a combustion air supply line which is configured to supply the heat-exchanged combustion air from the duct to a burning portion of the steam-reforming device. a steam-reforming device for generating reformed gas by steam-reforming natural gas; a methanol synthesis device for synthesizing methanol from the reformed gas; a first gasoline synthesis column (30, 30A) for synthesizing gasoline from the methanol, comprising: reaction tubes for synthesizing gasoline from methanol, wherein two types of catalysts including a dimethyl ether synthesis catalyst for synthesizing dimethyl ether from methanol and a gasoline synthesis catalyst for synthesizing gasoline from dimethyl ether are charged inside the reaction tube in two stages; and a duct which allows combustion air to flow outside the reaction tubes, wherein the duct is configured so that heat exchange is carried out between synthesis heat generated in the reaction tubes and the combustion air that flows through the duct, wherein the duct is configured so as to allow the combustion air to flow outside a portion of the reaction tubes in which the dimethyl ether synthesis catalyst is charged and then to flow outside a portion of the reaction tubes in which the gasoline synthesis catalyst is charged; reaction tubes for synthesizing gasoline from methanol, wherein two types of catalysts including a dimethyl ether synthesis catalyst for synthesizing dimethyl ether from methanol and a gasoline synthesis catalyst for synthesizing gasoline from dimethyl ether are charged inside the reaction tube in two stages; and a duct which allows combustion air to flow outside the reaction tubes, wherein the duct is configured so that heat exchange is carried out between synthesis heat generated in the reaction tubes and the combustion air that flows through the duct, wherein the duct is configured so as to allow the combustion air to flow outside a portion of the reaction tubes in which the dimethyl ether synthesis catalyst is charged and then to flow outside a portion of the reaction tubes in which the gasoline synthesis catalyst is charged; a fan for feeding combustion air; a steam-combustion air heat exchanger configured to preheat the combustion air with steam; a flue gas-combustion air heat exchanger which is configured to preheat combustion air with flue gas that flows in a waste heat recovery portion of the steam-reforming device; a combustion air introduction line which is configured to introduce the preheated combustion air into the duct; and a combustion air supply line which is configured to supply the heat-exchanged combustion air from the duct to a burning portion of the steam-reforming device.