Formula (1) [wherein A1 represents NR8 or the like, A2 and A3 represent N or the like, Q represents O or S, R1 represents a C1-C6 chain hydrocarbon group or the like, R2, R4 and R5 represents the same or different hydrogen atom, and R3 represents the following formula group J1, group J2 or group J3 {wherein R3a, R3b, R3c and R3e are the same or different and have one or more halogen atoms. An optionally substituted C1-C6 alkyl group, R3d and R3f represent a C1-C6 chain hydrocarbon group, etc., R6, R7 and R8 are the same or different and represent a C1-C6 chain hydrocarbon group, etc. n represents 0, 1 or 2. ] And the N-oxide thereof have an excellent control effect against pests.式（１）［式中、Ａ１はＮＲ８等を表し、Ａ２及びＡ３はＮ等を表し、ＱはＯ又はＳを表し、Ｒ１はＣ１－Ｃ６鎖式炭化水素基等を表し、Ｒ２、Ｒ４及びＲ５は同一又は相異なり水素原子等を表し、Ｒ３は、下式基Ｊ１、基Ｊ２又は基Ｊ３｛式中、Ｒ３ａ、Ｒ３ｂ、Ｒ３ｃ及びＲ３ｅは同一又は相異なり１以上のハロゲン原子を有していてもよいＣ１－Ｃ６アルキル基等を表し、Ｒ３ｄ及びＲ３ｆはＣ１－Ｃ６鎖式炭化水素基等を表し、Ｒ６、Ｒ７及びＲ８は同一又は相異なりＣ１－Ｃ６鎖式炭化水素基等を表し、ｎは０、１又は２を表す。］で示される縮合複素環化合物及びそのＮ－オキシドは有害生物に対して優れた防除効力を有する。
