A gas purification method, whereby it becomes possible to reduce the amount of an adsorbent, reduce the size of an adsorption column to a great extent, and also reduce the amount of a reproduced gas in the adsorption/removal of carbon dioxide and water that are impurities contained in a gas to be purified, and it also becomes possible to reduce running cost. The gas purification method comprises bringing a gas to be purified which contains carbon dioxide as an impurity at a partial pressure of 35 Pa or less into contact with an adsorbent comprising a Faujasite-type zeolite in which the cation is sodium and of which the temperature for the regeneration by heating is set at 160 to 240 DEG C inclusive, thereby adsorbing and removing carbon dioxide. Alternatively, the gas purification method comprises bringing the gas to be purified into contact with an adsorbent comprising a Faujasite-type zeolite in which the cation is lithium and which has been subjected to initial activation at 300 DEG C or higher to thereby adsorb and remove carbon dioxide and then regenerating the gas by heating at 240 DEG C or lower.