A fused heterocyclic compound the formula (1): wherein A1 represents —NR8—, and the like; A2 represents a nitrogen atom, and the like; A3 represents a nitrogen atom, and the like; R1 represents a C1-C6 chain hydrocarbon group optionally having one or more atoms or groups selected from Group X, and the like; R2, R3, R4, and R5 are same or different and represent independently a C1-C6 chain hydrocarbon group optionally having one or more halogen atoms, and the like; R6 and R7 are same or different and represent independently a C1-C6 chain hydrocarbon group optionally having one or more atoms or groups selected from Group X, and the like; R8 represents a C1-C6 chain hydrocarbon group optionally having one or more atoms or groups selected from Group W, and the like; n represents 0, 1 or 2. The compound has an excellent activity of controlling pests.