There are provided a polyolefin-based resin composition that is substantially prevented from suffering from oxidative deterioration of polyolefin resin and stably used even when positioned in contact with or near to vinyl chloride-based resins, as well as a combination of a vinyl-chloride-based resin molded article and a molded article made of the polyolefin-based resin composition. The polyolefin-based resin composition used in contact with or near to vinyl chloride-based resins, comprises (A) 100 parts by mass of a polyolefin-based resin; and (B) 0.01 to 5 parts by mass of a phenol-based antioxidant containing no aliphatic ester group and/or a sulfur-based antioxidant containing no aliphatic ester group, and may further contain, if required, 0.01 to 3 parts by mass of a metal deactivator containing no aliphatic ester, and 50 to 250 parts by mass of a metal hydrate and/or a metal hydroxide. In the combination of the vinyl-chloride-based resin molded article and the polyolefin-based molded article, both the molded articles are positioned in contact with or near to each other, and the polyolefin-based molded article is made of the above polyolefin-based resin composition.