Disclosed herein is a toothbrush with tapered bristles and method of manufacturing such toothbrushes. The toothbrush is characterized in that the tapered end of each bristle is 0.02mm or less of diameter. The bristle is tapered starting at a position of 3.5mm or less from an end, and is made of polyethylene terephthalate or polybutylene terephthalate. The method of this invention consists of the steps of dipping 3.5mm portions from ends of monofilaments for toothbrushes into erosive chemicals such as sulfuric acid or sodium hydroxide until the dipped portions of the monofilaments are completely eroded, neutralizing the shortened monofilaments prior to rinsing and drying them, and implanting the shortened monofilaments on a toothbrush. Thereafter, the shortened monofilaments are ground using a 240grit silicone carbide sheet at 2600 to 2700rpm for 3 to 10sec, a 320grit silicone carbide sheet at same speed for 3 to 10sec, and a 400grit silicone carbide sheet at same speed for 3 to 10sec. The toothbrush of this invention enjoys advantages of proper flexibility and softness, improved feeling while brushing, and excellent scaling ability.