The present invention provides a compound represented by formula (I) (in the formula, B1 and B4 each independently represents a carbon atom, nitrogen atom or the like B2 and B3 each independently represents a nitrogen atom or the like R4 represents a hydrogen atom, halogeno group or the like Ar represents an unsubstituted or substituted C6-10 aryl group or the like Q represents a substituted phenyl group, substituted pyridyl group or the like) or salt thereof, and a harmful organism control agent including the compound or salt thereof.本發明提供一種化合物或其鹽、及含有該化合物或鹽之有害生物防除劑,該化合物係以式(I)(式中,B1及B4各自獨立地表示碳原子、氮原子等;B2及B3各自獨立地表示氮原子等;R4表示氫原子、鹵素基(halogeno group)等;Ar表示未經取代或具有取代基之C6~10芳基等;Q表示具有取代基之苯基、具有取代基之吡啶基等)表示。
