PROBLEM TO BE SOLVED: To provide a toothbrush in which deformation rigidity and strength of a bristle embedded base can be improved while excellent operability is maintained with the brush having a bristle embedded portion formed by molding a back molded portion on the back side of the bristle embedded base.SOLUTION: The bristle embedded portion 17 includes: a bristle embedded base 12 a bristle tuft 14 having a molten lump 15 by one end part 14a heated and melted and a back molded portion 16 that is molded by covering the back side of the bristle embedded base 12. The peripheral wall 19 of the bristle embedded base 12 has, in the tip end part of the bristle embedded portion 17, a curved peripheral part 21 projectingly curved toward the tip end direction. The transplantation holes 13 have a tapered opening peripheral part 13a in which a cross sectional area is taperingly expanded on the bottom face 20a of a transplantation recess 20. The peripheral wall 19 at the tip end with the curved peripheral part 21 includes a thick part 22 having the largest thickness inward in a part between the outer edges of the tapered opening peripheral part 13a, 13a of the pair of tip end transplantation holes 13, 13 near the peripheral wall 19.COPYRIGHT: (C)2012,JPO&INPIT【課題】植毛基部の背面側に背面成形部を成形して植毛部が形成される歯ブラシによる優れた操作性を保持したまま、植毛基部の変形剛性や強度を向上させることのできる歯ブラシを提供する。【解決手段】植毛部17は、植毛基部12と、加熱溶融された片端部14aによる溶融塊15を有する毛束14と、植毛基部12の背面側を覆って成形された背面成形部16とを備えている。植毛基部12の周縁壁19は、植毛部17の先端部分に先端方向に突出して湾曲する湾曲周縁部21を備えている。植毛孔13は、植毛用凹部20の底面20aに断面積をテーパー状に拡径させたテーパー状開口周縁部13aを備えている。湾曲周縁部21を備える先端部分の周縁壁19は、当該周縁壁19の近傍の1対の先端植毛孔13’,13’のテーパー状開口周縁部13a’,13a’の外縁の間の部分において、内側に肉厚が最も大きくなった厚肉部22を備えている。【選択図】図2
