NOVELTY - Production of synthesis gas for Fischer-Tropsch synthesis, comprises adsorbing impurities contained in natural gas by active carbon to remove impurities; hydrogenating sulfur content in natural gas in the presence of hydrogenation catalyst and desulfurizing sulfur content; supplying natural gas with hydrogen; reacting natural gas, carbon dioxide, and steam in the presence of catalyst for reforming to obtain synthesis gas.    USE - For producing synthesis gas for Fischer-Tropsch synthesis (claimed).    ADVANTAGE - The method is capable of producing the synthesis gas for synthesis having hydrogen/carbon monoxide molar ratio suitable for Fischer-Tropsch synthesis (1.9-2.1) and no soot mixed, can suppress the side reaction in a hydro-desulfurizer and the deterioration of the catalyst for reforming, and is applicable to a large scale production equipment (commercial plant).    DETAILED DESCRIPTION - Production of synthesis gas for Fischer-Tropsch synthesis, comprises:    (1) adsorbing impurities contained in natural gas by active carbon to remove the impurities;    (2) hydrogenating sulfur content in natural gas in the presence of hydrogenation catalyst under a partial pressure of hydrogen of 100-00 kPa and desulfurizing the sulfur content by an adsorbing agent;    (3) supplying the natural gas after the hydro-desulfurizing step with hydrogen at 0.05-0.1 mol to 1 mol of carbon of hydrocarbon in natural gas;    (4) reacting natural gas, carbon dioxide, and steam in the presence of a catalyst for reforming to obtain synthesis gas for Fischer-Tropsch synthesis; and    (5) cooling the synthesis gas for the Fischer-Tropsch synthesis at 2000-4000degreesC/sec.    An INDEPENDENT CLAIM is also included for a production apparatus of synthesis gas for Fischer-Tropsch synthesis, comprising:    (1) an active carbon adsorbing vessel (11) containing active carbon for adsorbing and removing impurities in natural gas;    (2) a hydro-desulfurizer (13) containing a hydrogenation catalyst for hydrogenating sulfur content in natural gas and adsorbing agent for adsorbing sulfur content in natural gas;    (3) a pressure controller for controlling a partial pressure of hydrogen in the hydro-desulfurizer to be 100-200 kPa;    (4) a hydrogen supplying device for supplying hydrogen to the natural gas between the hydro-desulfurizer and a reactor (15), the reactor containing a catalyst for reforming which is for obtaining synthesis gas for the Fischer-Tropsch synthesis by reacting natural gas, carbon dioxide and steam; and    (5) a cooler for cooling the synthesis gas for the Fischer-Tropsch synthesis at a cooling rate of 2000-4000o?C/sec.    DESCRIPTION OF DRAWING(S) - The figure is a schematic diagram showing a producing apparatus of the synthesis gas for Fischer-Tropsch synthesis.    Active carbon adsorbing vessel (11)    Hydro-desulfurizer (13)    Reactor (15)    Soot filter (20)    Steam drum (22)    Compressor (25)    Steam line (52)