The present invention provides a compound represented by formula (I), (in the formula, A1 and A2 each independently represents a carbon atom or a nitrogen atom； X1 represents an unsubstituted or substituted C1-6 alkyl group or the like； n represents an integer of 0 to 4； R1 represents an unsubstituted or substituted C1-6 alkylthio group or the like； B1 and B4 each independently represent a carbon atom, a nitrogen atom or the like； R2 and R3 each independently represent a hydrogen atom, a halogeno group or the like； Ar represents an unsubstituted or substituted C6-10 aryl group or the like) or a salt thereof, and a harmful organism control agent including thereof.
