To provide a tapered bristle having excellent cleaning property and durability while keeping excellent touch and flexibility characteristic to a tapered bristle made of a polyamide resin, and to provide a brush using the same.

The tapered bristle 1 has a tapered part at least at one end of a cut bristle made of a synthetic resin monofilament, and has a core/sheath composite structure in which the core part is made of a polyamide resin and the sheath part is made of a polyester resin. The tapered part 2 is composed of a core tapered part 4 in which the core part is exposed acutely, and a sheath tapered part 5interposed between the core tapered part 4 and a straight part. The length of the core tapered part 4 is 50 to 95% of the length of the tapered part.