A cross-linkable nitrile rubber composition that includes a nitrile group-containing copolymer rubber (A), silica (B1), clay (B2), calcium carbonate (B3), and a polyamine-based cross-linking agent (C). A total amount of the silica (B1), the clay (B2), and the calcium carbonate (B3) is 150 to 200 parts by weight with respect to 100 parts by weight of the nitrile group-containing copolymer rubber (A), a content ratio of the silica (B1) is greater than 0 wt % and 50 wt % or less with respect to the total amount of the silica (B1), the clay (B2), and the calcium carbonate (B3), and a content ratio of the clay (B2) and the calcium carbonate (B3) is 30:70 to 90:10 in a weight ratio of “clay (B2):calcium carbonate (B3)”.