The object of the present invention is to provide a flame-resistant fiber which possesses low negative effects on the environment and humans, such as emission of hazardous substances, which displays excellent both flame and weather resistance, and which does not reduce spinnability and fiber strength, and is able to provide a fiber molding obtained from the fiber. A flame-resistant fiber comprising at least one type of phosphazene derivatives selected from cyclic phosphazene derivatives and linear phosphazene derivatives, a hindered amine derivative containing specific groups, and a thermoplastic resin, wherein the fiber contains 0.25-5.0 wt % of the phosphazene derivative and 0.025-3.0 wt % of the hindered amine derivative, and the fiber fineness is 0.01-100 dtex.