The present invention provides a method of manufacturing a toothbrush having needle-shaped bristles, and a toothbrush manufactured by the method. The toothbrush manufacturing method of the present invention includes the step of partially tapering ends of bristles, which are made of polyester and are set in a toothbrush body, through a physical grinding process, and the step of completing of a process of tapering the partially tapered bristles by immersing the partially tapered bristles in a chemical. The present invention makes it possible for toothbrush bristles to be tapered through a simple process. Furthermore, the present invention solves conventional difficulties occurring in tapering bristles after setting them in toothbrush bodies.