A fused heterocyclic compound or an N-oxide thereof represented by formula (1):wherein A1 represents NR7 or the like, A2 and A3 represent N or the like, Q represents O or S, R1 represents a C1 to C6 chain hydrocarbon group or the like, R2 and R4 are the same or different and represent a hydrogen atom or the like, R3 represents group J1, group J2 or group J3 of the following formulae:wherein R3a, R3b, R3c and R3e are the same or different and represent a C1 to C6 alkyl group optionally having one or more halogen atoms or the like； and R3d and R3f represent a C1 to C6 chain hydrocarbon group or the like；R5, R6 and R7 are the same or different and represent a C1 to C6 chain hydrocarbon group or the like； and n represents 0, 1 or 2, has an excellent control effect on pests.
