PROBLEM TO BE SOLVED: To provide a toothbrush capable of highly efficiently brushing teeth while holding a state of pushing the bristle ends at the tip of a brush part against a considerable contact area from an interdental part of a tooth face to a smooth part without applying so much force thereto when brushing especially anterior teeth.SOLUTION: When viewing a brush part 16 from the side, this toothbrush is formed with a small crest part 17 where a ridge line (s) formed by connecting the tips of bristle bundles 15a and 15b is disposed at the tip part of the brush part 16, and a large crest part 18 that continues rearward the small crest part 17, and having the length L2 in the brush part longitudinal direction X larger than that of the small crest part 17, wherein the height of the large crest part 18 from the bristle-filling base 11 is gradually formed higher from a trough bottom part formed between itself and the small crest part 17, toward a top portion 18a. The top portion 17a of the small crest part 17 is formed higher than the top portion 18a of the large crest part 18 and the length of a line segment L formed by connecting the top portion 17a of the small crest part 17 to the top portion 18a of the large crest part 18 is defined to 4.3-9.2 mm. The length of a perpendicular drawn from the trough bottom part 19 to the line segment L is defined to 0.8-1.6 mm.COPYRIGHT: (C)2010,JPO&INPIT【課題】特に前歯に対してブラッシングを行う際に、あまり力を入れずに、歯面の歯間部から平滑部に亘って相当の接触領域でブラシ部の先端の毛先を押し当てた状態を保持して、効率良くブラッシングを行うことのできる歯ブラシを提供する。【解決手段】ブラシ部16を側面から見たときに、毛束15a,15bの先端を結んだ稜線sが、ブラシ部16の先端部分に配置される小山部17と、小山部17の後方に連続する、小山部17よりもブラシ部長手方向Xの長さL2が大きく、且つ大山部18は、小山部17との間の谷底部から頂部18aまで植毛台11からの高さが徐々に高く形成されている。小山部17の頂部17aは、大山部18の頂部18aよりも高くなっており、小山部17の頂部17aと大山部18の頂部18aとを結んだ線分Lの長さは4.3~9.2mmとなっている。谷底部19からこの線分Lに降ろした垂線Dの長さは0.8~1.6mmとなっている。【選択図】図1
