A polyamide resin composition is provided which contains an anti-aging agent together with a deterioration inhibitor, such as a metal compound or a silica-based inorganic compound, for preventing deterioration caused by, for example, an acid component or a halogen component contained in a refrigerant or an oil, and which satisfactorily produces an anti-aging effect expected by adding the anti-aging agent. For producing a polyamide resin composition containing an (a) polyamide resin, a (b) polyolefin-based elastomer, at least one (c) deterioration inhibitor selected from the group consisting of hydroxides, oxides and basic salts of divalent or trivalent metals, and silica-based inorganic compounds, and a (d) anti-aging agent, a mixture prepared by mixing and kneading the (c) deterioration inhibitor and (b) polyolefin-based elastomer and a mixture prepared by mixing and kneading the (a) polyamide resin and the (d) anti-aging agent are mixed and kneaded.