Crosslinkable nitrile rubber composition and crosslinked rubber material

Provided is a crosslinkable nitrile rubber composition containing: a highly saturated nitrile rubber (A) containing α,β-ethylenically unsaturated nitrile monomer units in a ratio of 5-50 wt%, the highly saturated nitrile rubber (A) having an iodine value of 120 or less; polysaccharide polymer short fibers (B) having an average fiber diameter of 1 µm or less; and a crosslinking agent (C); the content ratio of the polysaccharide polymer short fibers (B) being 0.5-30 parts by weight with respect to 100 parts by weight of the highly saturated nitrile rubber (A).