To provide a method for manufacturing an interdental cleaning tool that can prevent deformation of a core base at molding of a cleaning flexible part using an elastomer material, thereby effectively preventing occurrence of molding failure of the cleaning flexible part. The method in the present invention includes: a base part molding step of providing first metal molds 30 and 31 for molding base parts with a plurality of first molding spaces 32 aligned in parallel and including core base molding sections 32a and handle base molding sections 32b, providing the first metal molds 30 and 31 with connection part molding sections 35 to communicate with the adjacent handle base molding sections 32b, and supplying a synthetic resin material with a fiber material at a time to the plurality of first molding spaces 32 from gates 34 to form a plurality of base parts at a time； and a flexible part molding step of setting the core bases of the base parts into second metal molds, holding the core bases at two or more longitudinal portions by a plurality of pairs of hold pins in the second metal molds, each pair including two pins, and charging an elastomer material into the cleaning flexible part molding spaces.本發明之課題係在於提供可防止當使用彈性體材料成形清掃用軟質部時之芯部的變形，可有效地防止清掃用軟質部的成形不良產生之齒間清掃具的製造方法。在成形基材部之第1模具(30、31)，呈複數個並排狀設置由芯基材部成形部(32a)與把手基材部成形部(32b)所構成的第1成形空間(32)，並且設置將鄰接的把手基材部成形部(32b)連通的連結部成形部(35)，從閘口(34)對複數個第1成形空間(32)同時地供給添加有纖維材的合成樹脂材料，同時成形該複數個基材部之基材部成形製程；和將該複數個基材部安裝於第2模具，以設在第2模具之2支保持銷為1組的複數組保持銷在芯本體的長度方向之至少2部位加以保持的狀態下，對清掃部成形空間填充彈性體材料來形成軟質部之軟質部成形製程。
