The purpose of the present invention is to obtain a superior antiviral processed article having water resistance and wash durability, by heating a resin molded product at atmospheric pressure or elevated pressure while subjecting the resin molded product to contact with a treatment liquid containing an antiviral compound (A) comprising a quaternary ammonium halide having a molecular weight of 1500 or less, and thereby fixing the antiviral compound (A) to at least the surface of the resin molded product.本發明係藉由使含有由分子量1500以下之四級銨鹵化物構成的抗病毒性化合物(A)之處理液與樹脂成形品在接觸的狀態下，於常壓或加壓下實施加熱處理，而使該抗病毒性化合物(A)至少固定於該樹脂成形品之表面，而獲得具備有耐水性、洗滌耐久性之優良的抗病毒加工製品。
