To exhibit an insect-repelling effect while minimizing insect repellent intake by people, etc., and to prolong said insect-repelling effect. This insect repellent fiber (1), which can emit an insect repellent, comprises a core part (2) which contains an insect repellent (4) and which is formed from a thermoplastic resin, and a sheath part (3) which contacts the outer surface of and covers the core part and which is formed from a thermoplastic resin. The crystallinity of the thermoplastic resin configuring the sheath part is less than or equal to the crystallinity of the thermoplastic resin configuring the core part.本發明之防蟲纖維課題為既可抑制人類等對於防蟲劑之攝取量又可發揮防蟲效果，並且可使防蟲效果容易持續。本發明之防蟲纖維，其係可釋出防蟲劑的防蟲纖維(1)，係具有：芯部(2)，其係含有防蟲劑(4)且由熱塑性樹脂構成；鞘部(3)，其係與芯部的外表面接觸並覆蓋芯部，且由熱塑性樹脂構成。構成鞘部的熱塑性樹脂之結晶化度係等於或小於構成芯部的熱塑性樹脂之結晶化度。
