PROBLEM TO BE SOLVED: To provide a toothbrush having a light condensing part in a specific region of a raised bristle surface of the head part, which toothbrush can stably maintain the light condensing efficiency of the light condensing part.SOLUTION: The toothbrush is provided with a main body that includes: a head part 4 having a raised bristle surface 4a on which bristles 210 are raised a grip part and a neck part. The inside of the main body is provided with: a light-emitting part 50 that emits light L toward a tooth surface 99a through a specific region 4c of the raised bristle surface 4a and a light receiving part 51 that receives radiant light L caused by the emitted light from the tooth surface through the specific region 4c. The presence or absence of plaque on the tooth surface 99a is determined based on an output of the light receiving part 51. A part of a housing constituting the specific region 4c is arranged with a light receiving and condensing part 53 that condenses the radiant light L from the tooth surface 99a toward a light receiving surface of the light receiving part 51. A region that includes the specific region 4c of the raised bristle surface 4a of the head part 4 and is wider than the specific region 4c is flattened.SELECTED DRAWING: Figure 4COPYRIGHT: (C)2018,JPO&INPIT【課題】ヘッド部の起毛面のうち特定領域に集光部を備えた歯ブラシであって、集光部の集光効率を安定して維持できるものを提供すること。【解決手段】毛210が立設された起毛面4aを有するヘッド部4、グリップ部、および、ネック部を含む本体を備える。本体の内部に、歯表面99aへ向けて起毛面4aのうちの特定領域4cを通して光Lを照射する発光部50、および、その光による歯表面からの放射光L′を特定領域4cを通して受光する受光部51を備える。この受光部51の出力に基づいて歯表面99aにおける歯垢の有無が判定されるようになっている。特定領域4cをなす筐体部分に、歯表面99aからの放射光L′を受光部51の受光面へ向けて集光する受光集光部53が配置されている。ヘッド部4の起毛面4aのうち特定領域4cを含み且つ特定領域4cよりも広い領域が平坦になっている。【選択図】図4
