The invention provides a brush bristle and a brush roll that exhibit a suitable abrasive force and that can reduce or eliminate the abrasion of a mill roll as much as possible. The brush bristle is for use in a brush roll B configured to scour a mill roll for rolling a metal sheet S, and includes one or more monofilaments 2 made of a thermoplastic resin containing abrasive particles. The abrasive particles have a hardness lower than the hardness of the mill roll, and higher than the hardness of the metal sheet S.