A gas purifier includes an air passage. An adsorption removal device, which includes a regenerable adsorbent for adsorbing chemical contaminants from non-purified air and separating the adsorbed contaminants through a regeneration process, and a gas purification unit, which performs gas-liquid contact with a porous film to separate and removes contaminants from the non-purified air into a liquid, are arranged in an air passage. The chemical contaminants are adsorbed and removed by the adsorption removal device.