The 180 toothbrushes out of 18 models( ten brushes for each model) were used for this examination among the toothbrushes for adults which were sold in the domestic markets. After three-month brushings through a roll ing method and Bass method were practiced with Toothbrush Stroke Tester which reproduced brushing methods outside the mouth, I investigated the morphology bristle tips of using scanning electron microscope(SEM). The conclusions are as follows. 1. Soft bristle toothbrushes(of 8 models out of 9 models) were badly damaged at the bristles end after 3 month toothbrushing. 2. Medium bristle toothbrushes(of four models out of five models) were irregularly worn at the bristles end after 3 month toothbrushing. 3. Hard bristle toothbrushes(of three models out of four models) were chisel-shapedly worn at the bristles end after 3 month toothbrushing. 4. Taper-shaped toothbrushes were very irregularly bent at the bristles end after 3 month toothbrushing. 5. It was examined in the bristle stiffness that soft bristle toothbrushes were found in 9 models(50.00%), medium bristle toothbrushes in 5 models(27.78%), and hard-bristle toothbrushes in 4 models(22.22%).