To obtain a chlorine-trapping agent composition exhibiting extremely high chlorine-trapping capability within a wide combustion temperature range from a low temperature to a high temperature and effectively prevented elution of a chloride from combustion residue, and a chlorine-containing resin composition having the chlorine-trapping agent composition incorporated therein.

The chlorine-containing resin composition comprises a chlorine- containing resin and, incorporated therein, the chlorine-trapping agent composition comprising (A) calcium carbonate as a main component, (B) an oxide exhibiting chlorine-trapping capability within a low temperature range and/or at least one of oxides, carbonates and sulfates exhibiting chlorine-trapping capability within a moderate to high temperature range.