Formula (1) [wherein A1 represents NR7, etc., A2 and A3 represent N, etc., Q represents O or S, R1 represents a C1-C6 chain hydrocarbon group, etc., and R2 and R4 are the same Or R3 represents a hydrogen atom or the like, and R3 represents the following group J1, group J2 or group J3 {wherein R3a, R3b, R3c and R3e may be the same or different and each may have one or more halogen atoms. -C6 alkyl group and the like, R3d and R3f represent a C1-C6 chain hydrocarbon group and the like, R5, R6 and R7 are the same or different and represent a C1-C6 chain hydrocarbon group and the like, n is 0, 1 or 2 is represented. ] Or a N-oxide thereof having an excellent control effect against pests.式（１）［式中、Ａ１はＮＲ７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及びＲ４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、Ｒ５、Ｒ６及びＲ７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又はその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。
