To prevent the bristle tips of a toothbrush from opening and to epochally solve such drawback.

The case for opening of the bristle tips lies in that an undue brushing pressure is exerted to the toothbrush in order to allow the bristle tips to reach the tooth alignment and recessed surfaces and the toothbrush is forced to be sued in the half open state of the bristle tips from the time of a brand new toothbrush on the counter projecting surfaces. A cartridge type shown in Figure 3 is adopted for this toothbrush in order to solve this unavoidability. The corrugated toothbrush bristles can be freely crimpled by the elongation and contraction of a corrugated bristle root mat 10 to the tooth and the ruggedness and simultaneously the wave stress thereof is converted and generated to a lever and the lever axis of rubber surface skin 5 and the springs over the entire part of the length of the bristles and the waves of the bristle tips coming in contact with the respective lever ends are converted and generated to the brushing moment of the stress enclosing the respective tooth profiles in an uprightly standing direction.