PURPOSE: To provide the titled composition having improved thermal stability even containing a large amount of carbon, and giving a molded product storable without any troubles, by adding a small amount of a specific organotin compound to a base resin.

CONSTITUTION: 100pts.wt. of a halogen-containing resin containing electrically conductive carbon is compounded with 0.1W8pts.wt., preferably 0.5W5pts.wt. of an organotin compound of formula I (R and R' are alkyl, aryl, alkylaryl, arylalkyl, or cycloalkyl; X and Y are aromatic or aliphatic carboxilic acid residue; n is 0.1W2), formula II or formula III (R" is aromatic or aliphatic hydrocarbon group) or formula IV W formula VI (n' is 1W4; R" is aromatic or aliphatic hydrocarbon grup which may be substituted with alkoxy).