Disclosed are a method for manufacturing a spherical brush having highly dense bristles for cleaning a periodontal pocket easily and a cylindrical brush having the brush bristles at the whole globe of the tip thereof, and a brush using the manufacturing method. A fiber bundle, which is composed of a number of short fibers prepared by cutting long fibers, is gripped between the U-shaped loop wires of one set arranged to cross each other. The open ends of the wire loops are pulled and twisted in the opposite directions, so that the fibers at the portion gripped by the wires are compressed to reduce their sectional bundle areas. The elastic repulsion is established between the fiber bundles near the wire-gripped portion by the differences of the cross sectional areas between the free end fibers at both ends of the wire-gripped portion, and is utilized to diverge the free end fibers radially to the circumference from the wire-gripped portion.
