The present invention relates to a compound of the formula [I]: wherein R1 is C1-6 alkyl or C1-6 haloalkyl; n is 0, 1 or 2; X is (1) group of —NR2R3 wherein R2 and R3 independently represent (i) hydrogen or (ii) C1-6 alkyl which may optionally be substituted with pyridyl, (2) group of —N═CHOR4 wherein R4 represents C1-6 alkyl, (3) group of —N═CHNR6R7 wherein R6 and R7 independently represent (i) hydrogen or (ii) C1-6 alkyl, (4) group of —N═CHAr wherein Ar represents phenyl which may optionally be substituted with substituents selected from the group consisting of hydroxy and C1-3 alkoxy, or (5) pyrrolyl; R5 is optionally substituted alkyl or optionally substituted acyl; R8 is (1) halogen, (2) C1-6 haloalkyl, (3) C1-6 haloalkoxy or (4) phenyl which may optionally be substituted with C1-6 haloalkyl; A is (1) nitrogen atom or (2) group of wherein R9 is chlorine atom or cyano; and B is nitrogen atom or or a salt thereof. The compounds [I] or their salts have excellent insecticidal activities and less toxicity against fishes. Therefore, the agrochemical compositions containing the compound [I] or a salt thereof can protect crops, etc. from harmful pests so as to contribute to an agricultural success.