PURPOSE: To provide a method for efficiently refining krypton and xenon continuously in a high purity by a simple apparatus structure.

CONSTITUTION: A method for refining xenon and krypton comprises a concentrating step of concentrating the xenon and krypton by introducing liquefied oxygen containing the krypton and the xenon to a concentrating tower 3, a catalytic refining step by using a catalytic reaction cylinder 15 of copper and chromium composite catalyst to react hydrocarbons with oxygen to be removed after bottom liquid of the tower is vaporized and an adsorber 18 for removing carbon dioxide and water of a reactive product, and a catalytic refined gas-circulating step for branching the gas after discharging from the adsorber, introducing the gas in one branch to the bottom of the tower, and diluting the hydrocarbons in the bottom liquid. Thus, the method further comprises a control step of an input of gas containing the krypton and the xenon after the catalytic reaction step for reintroducing it to a lower part of the tower, a step of removing the oxygen by again liquefying the other, introducing and refining it by a deoxygenating tower 23, and a step of separating the xenon and the krypton by refining the bottom liquid of the deoxygenating tower by a separating tower 28.