Disclosed is a harmful arthropod control composition comprising, as an active ingredient, a fused heterocyclic compound represented by formula (1) [wherein A 1 and A 2 independently represent a nitrogen atom or the like R 1 and R 4 independently represent a halogen atom or the like R 2 and R 3 independently represent a halogen atom or the like R 5 and R 6 independently represent a linear C1-C6 hydrocarbon group which may be substituted, or the like (provided that both R 5 and R 6 cannot represent a hydrogen atom simultaneously) and n represents 0 or 1]. The harmful arthropod control composition has an excellent efficacy to control harmful arthropods.