To thoroughly remove the plaque and residual foreign matters stuck to teeth by extending many hair-like brush materials outward in the radial direction from the outer peripheral face of a circular section provided with a shaft hole at the center of a rotary brush, and protruding a spindle rotatably supporting the rotary brush on one end side of a shank member.

A rotary brush 5 is provided with a circular section having a round shaft hole at the center, an outer peripheral section uniformly planted with many hair-like brush materials 6 on the circular section is formed into a nearly disk-like roll shape, and the rotary brush 5 is fitted to a shank member 1 to form a toothbrush. When the rotary brush 5 is to be fitted to the shank member 1, a spindle is inserted into the shaft hole of the rotary brush 5, the right and left extension pieces 2, 3 are opened outward, both ends of the spindle are inserted into coupling grooves, and the rotary brush 5 is rotatably held by the tip side 1b of the shank member 1. The hair tips of the hair-like brush materials enter between teeth, and the plaque and residual foreign matters stuck to teeth can be thoroughly removed.