PURPOSE: To provide the titled compsn. which can be easily vulcanized to give a vulcanized product which is excellent in oil resistance and various characteristics, by blending sulfur or a sulfur-contg. org. compd. with a 1-acetoxy-1,3- butadiene (co) polymer.

CONSTITUTION: Sulfur and/or a sulfur-contg. org. compd. are/is blended with l-acetoxy-1,3-butadiene (ABD) polymer or a copolymer of ABD and a monomer copolymerizable therewith. The monomer copolymerizable with ABD is used to improve mechanical properties, etc. of the polymer. Example thereof are alkyl (meth) acrylates, vinyl acetate and styrene. The amount of ABD to be copolymerized is pref. 0.5wt% or more. When the amount of ABD to be copolymerized is less than 0.5wt%, satisfactory effect can not be obtd. When it is 70wt% or more, a vulcanizable compsn. having excellent oil resistance can be obtd.