PURPOSE: To provide the titled compsn. which gives electrically conductive moldings having a high distortion temperature, less heat shrinkability, and excellent surface texture and strength, by incorporating special carbon black in a copolymer having a specified specific viscosity and composed of vinyl chloride and an alkyl (meth)acrylate.

CONSTITUTION: 15W40pts.wt. carbon black having an oil absorption of 300W 400ml/100g and a specific surface area of 800m2/g or above, 0W5pts.wt. lubricant, 0W5pts.wt. plasticizer and 0W20pts.wt. impact-resistant acid, arce incorporated in 100pts.wt. copolymer having a specific viscosity of 0.16W0.31 and composed of 85W99.5wt% vinyl chloride, 0.5W15wt% alkyl (meth)acrylate and 0W10wt% monomer copolymerizable therewith, or polymer mixture having a specific viscosity of 0.16W0.31 and composed of the above copolymer and a vinyl chloride polymer. The proportions of monomer components in said polymer mixture are the same as those of monomer components in said copolymer.