The present invention provides: a heterocyclic compound which exhibits an excellent controlling effect against harmful arthropod, and which is represented by formula (I) (in the formula, Q denotes a group represented by Q1 or the like, A2 denotes a nitrogen atom or CR4a, A3 denotes a nitrogen atom or CR4b, A4 denotes a nitrogen atom or CR4c, and T denotes a C1-C10 linear hydrocarbon group having one or more halogen atoms, or the like)； and a composition that contains this compound and one or more components selected from the group consisting of group (a), group (b), group (c), group (d) and group (e) listed in the description.
