[Problem] To exhibit an insect-repelling effect while suppressing insect repellent intake by people, etc., and to prolong said insect-repelling effect.[Solution] This inject repellent fiber (1), which can release 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 the core part to cover 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.
