A storage method of storing a package with its contents under irradiation of light. At least part of the package is made of polyamide (A) which is obtained by polycondensation of a diamine component comprising 70 mol % or more of m-xylylenediamine and a dicarboxylic acid component comprising 70 mol % or more of α,ω-linear aliphatic dicarboxylic acid having 4 to 20 carbon atoms. The oxygen transmission of the package including polyamide (A) is reduced by irradiation of light, to prevent the spoilage of the contents.