NOVELTY - Argon gas containing oxygen, carbon monoxide, hydrogen, and nitrogen as an impurity, is pretreated. Carbon monoxide and hydrogen contained in argon gas are reacted with oxygen by contacting a ruthenium catalyst with argon gas, carbon dioxide and water are formed, and carbon monoxide and hydrogen are removed. Pressure-fluctuation adsorption method is performed using 3 or more pressure swing adsorption (PSA) towers in which PSA adsorption agent is filled. Temperature variation adsorption method is performed using temperature swing adsorption (TSA) tower in which TSA adsorption agent is filled.    USE - Purification of argon used as furnace atmosphere gas in silicon monocrystal furnace, ceramic sintering furnace, vacuum degassing furnace for manufacturing steel, and silicon plasma melting furnace for solar cell.    ADVANTAGE - The method provides highly purified argon using reduced energy.    DETAILED DESCRIPTION - Argon gas containing oxygen, carbon monoxide, hydrogen, and nitrogen as an impurity, is pretreated. Carbon monoxide and hydrogen contained in argon gas are reacted with oxygen by contacting a ruthenium catalyst with argon gas, carbon dioxide and water are formed, and carbon monoxide and hydrogen are removed. Pressure-fluctuation adsorption method is performed using 3 or more pressure swing adsorption (PSA) towers in which PSA adsorption agent is filled. The impurity in the mixed gas is adsorbed on the PSA adsorption agent by introducing mixed gas (from which carbon monoxide and hydrogen are removed through the pretreatment process) into the PSA adsorption towers, in the state where PSA adsorption towers are at a relatively high pressure. Semi-purified gas (G2) in which argon is enriched from the PSA adsorption tower, is adsorbed. The pressure of PSA adsorption tower is reduced, impurity is removed from the PSA adsorption agent, and gas from the PSA adsorption tower, is discharged. Washing gas is introduced into the PSA adsorption tower, and gas is discharged from the PSA adsorption tower. The internal pressure of the PSA adsorption tower which passed through adsorption process, and the internal pressure of a PSA adsorption tower which passed through the washing process, are equalized. The above process is repeatedly performed. Temperature variation adsorption method is performed using temperature swing adsorption (TSA) tower in which TSA adsorption agent is filled. The TSA adsorption agent in the tower adsorbs the impurity in the semi-purified gas on the TSA adsorption agent by introducing the semi-purified gas into the TSA adsorption tower at low-temperature adsorption temperature. Purified gas (G6) in which argon is enriched rather than the semi-purified gas is discharged from the TSA adsorption tower. The TSA adsorption agent in the TSA adsorption tower is heated to hot temperature, the TSA adsorption agent is regenerated by desorbing an impurity from the TSA adsorption agent, and an off gas is discharged from the TSA adsorption tower. The above process is repeated. Thus, argon purification is enabled. An INDEPENDENT CLAIM is included for argon refiner (X), which has a preprocessor for contacting a ruthenium catalyst in the argon gas, and reacting carbon monoxide and hydrogen contained in the argon gas, with oxygen, pressure fluctuation adsorption type gas separation apparatus (10), PSA adsorption towers and temperature variation adsorption type gas-separation apparatus (20).    DESCRIPTION OF DRAWING(S) - The drawing shows the schematic view of argon refiner.    Heater (2)    Reactor (3)    Adsorption apparatus (8)    Pressure fluctuation adsorption type gas separation apparatus (10)    Temperature variation adsorption type gas-separation apparatus (20)    Source gas (G0)    Semi-purified gas (G2)    Purified gas (G6)    Argon refiner (X)