To provide a polygonal toothbrush which promises removal of plaque by facilitating insertion of bristles into interdental gaps, and consequently also promises the effect of preventing periodontal disease and gingivitis or the effect of massaging gum or the like.

The toothbrush includes a brush material 1 attached to a rotary shaft 9 provided in a handle portion 13 by fitting a rotary shaft insert shaft thereof into the rotary shaft, and a guide plate for guiding the rotation of the rotary shaft insert shaft which is provided on the handle portion 13, in which the frictional resistance between the rotary shaft 9, the rotary shaft insert shaft, and the guide plate are variable. Otherwise, the brush material 1 is attached to the rotary shaft 9 of the handle portion 13 through a rotary shaft insert hole thereof so that the frictional resistance between the rotary shaft and the rotary shaft insert hole of the brush material is variable.