To provide a flameproof fiber and a flameproof textile product rich in durability without deteriorating mechanical characteristics of an original textile material, and to provide a method for producing the same.

At least one animal protein fiber selected from among silk protein fibers derived from a domesticated silkworm and a wild silkworm; wool fibers; keratin fibers; and collagen fibers or a textile product thereof is subjected to graft processing with a grafting agent including an acrylic acid derivative or a methacrylic acid derivative containing phosphate as an active ingredient.