To obtain a medium resistance elastomer composition, having a medium level of electrical resistivity (about 105 to about 1013Ω.cm), hardly fluctuating the electrical resistivity due to an environmental variation and having a low hardness.

This medium resistance elastomer composition comprises an epoxy group-containing acrylic rubber as an insulating elastomer and an electroconductivity imparter-containing acrylonitrile-butadiene copolymer rubber as an electroconductive elastomer. When the weight of the insulating elastomer is A and the weight of the electroconductive elastomer is B, the elastomer composition has 8.6×109Ω.cm electrical resistivity ρ2 of the composition at 7/3 ratio of the components A/B, 8.2×106Ω.cm electrical resistivity ρ1 of the composition at 3/7 ratio of the components A/B and 2.5×103Ω.cm electrical resistivity ρB of the composition at 0/10 ratio of the components A/B.