The purpose is to provide an interdental brush with a simple structure and reusable parts. The interdental brush (1) has a shaft portion (10) in which an internal passage (13) extended in the axial direction is opened at the tip and the base end, and a core (21) longer than the extended length of the internal passage (13). A brush (20) in which fibers (22) are flocked is provided in the entire area of the above, and a shaft portion (10) is inserted into an internal passage (13) from an opening (13b) on the proximal end side and one from the opening on the distal end side. The brush (20) having a protruding portion has a grip portion that changes its state between a gripping state in which the brush (20) is gripped to restrict axial movement and a release state in which the grip is released to allow axial movement. シンプルな構成で部品の再利用が可能な歯間ブラシを提供することにある。 歯間ブラシ（１）は、軸方向に延設された内部通路（１３）が先端及び基端に開口した軸部（１０）と、内部通路（１３）の延設長さより長い芯（２１）の全域に繊維（２２）が植毛されたブラシ（２０）とを備え、軸部（１０）は、基端側の開口（１３ｂ）から内部通路（１３）に挿入されて先端側の開口から一部が突出したブラシ（２０）を、把持して軸方向への移動を規制する把持状態と、把持を解除して軸方向への移動を許容する解除状態とに状態変化する把持部を有する。
