A nitrile rubber composition including a filler (B) in a content of 50 to 90 parts by weight and an adipic acid ester-based plasticizer and/or an ether ester-based plasticizer (C) in a content of 0 to 29.9 parts by weight in relation to 100 parts by weight of a nitrile group-containing highly saturated copolymer rubber (A) including an α,β-ethylenically unsaturated nitrile monomer unit in an proportion of 14 wt % or more and less than 21 wt %, and having an iodine value of 120 or less.