A flame-retarded composite fiber comprising (A) 85 to 15 parts by weight of a fiber comprising a polymer containing 17 to 86% by weight of a halogen, and 6 to 50% by weight of an Sb compound based on the polymer, and (B) 15 to 85 parts by weight of at least one fiber selected from the group consisting of natural fibers and chemical fibers, the total amount of the fibers (A) and (B) being 100 parts by weight. The composite fiber has not only the desired flame resistance but also excellent visual feeling, feeling of touchness, hygroscopic property, washing resistance, durability, and the like.