Abstract: A compound represented by formula (I) or a salt thereof, as well as a formulation for controlling harmful organisms, an insecticidal formulation, an acaricidal formulation, a nematicidal formulation, or a formulation for controlling or exterminating endoparasites, containing at least one compound selected from the group consisting of the compounds described above and salts thereof, as an active ingredient. In formula (I), Ar1 is a benzene ring or a 5- to 6-membered heteroaryl ring, R1 is a C1 to C6 alkyl group, a halogeno group, or the like, n represents the number of R1 and is 0, 1, 2, or 3, and in the case of n being 2 or more, two or more R1 may be the same as or different from one another, R2 is a C1 to C6 alkyl group, a C1 to C6 haloalkyl group, or the like, R3 is a hydrogen atom, a C1 to C6 alkyl group, a C1 to C6 alkylcarbonyl group, or the like, and AR2 represents a substituted or unsubstituted heteroaryl group.