PROBLEM TO BE SOLVED: To provide an interdental cleaner capable of enhancing cleaning efficiency on corner parts of triangular spots, and enhancing cleaning property on lateral faces of the teeth forming triangular spots.SOLUTION: An interdental cleaner comprises: a base part comprising a shaft part (20)； and a cleaning part (40). The shaft part (20) has a shape in which a cross section outer shape of the shaft part (20) in a plan face orthogonal to an axial direction of the shaft part (20) becomes gradually large from the tip side to the base end side of the shaft part (20). The cleaning part (40) has a cleaning part body (50) and a brush part (60), the brush part (60) has at least one brush group (61-68), and at least the one brush group (61-68) comprises a plurality of brushes (60a). Each brush (60a) of at least the one brush group (61-68) has a shape in which a projection dimension from the cleaning part body (50) becomes gradually large from the tip side to the base end side of the shaft part (20).SELECTED DRAWING: Figure 2COPYRIGHT: (C)2020,JPO&INPIT【課題】三角スポットの角部の清掃効率を高めるとともに、三角スポットを形成する歯の側面の清掃性を高めることが可能な歯間清掃具を提供すること。【解決手段】軸部（２０）を含む基部と清掃部（４０）とを備え、軸部（２０）は、軸部（２０）の先端側から基端側に向かうにしたがって軸部（２０）の軸方向と直交する平面での軸部（２０）の断面の外形が次第に大きくなる形状を有し、清掃部（４０）は、清掃部本体（５０）とブラシ部（６０）とを有し、ブラシ部（６０）は、少なくとも一つのブラシ群（６１～６８）を有し、少なくとも一つのブラシ群（６１～６８）は、複数のブラシ（６０ａ）を含み、少なくとも一つのブラシ群（６１～６８）の各ブラシ（６０ａ）は、軸部（２０）の基端側から先端側に向かうにしたがって次第に清掃部本体（５０）からの突出寸法が大きくなる形状を有すること。【選択図】図２
