PROBLEM TO BE SOLVED: To provide a rubber composition capable of manufacturing a molded body and a vibration-proof material good in balance of tensile strength and vibration proofing, and good in processability.SOLUTION: A manufacturing method of a rubber composition includes following processes. Process (1): a process of mixing a following component (A) of 100 pts.wt., a component (B) reinforcer of 1 to 150 pts.wt., a component (C) softener of 1 to 150 pts.wt., and a component (D) of 0.01 to 10 pts.wt. to manufacture a mixture. Process (2): and a process of mixing the mixture obtained from the process (A) and a component (E) a vulcanizer of 0.1 to 10 pts.wt. based on 100 pts.wt. of the component (A) to manufacture a rubber composition. Component (A): an ethylene-α-olefin-non-conjugated polyene copolymer rubber having an intrinsic viscosity [&eegr;] measured in tetralin at 135°C of 2.5 to 5 dl/g. Component (D): a compound represented by the formula (1) and/or a compound represented by the formula (2).
