A pyridazine compound represented by formula (1): wherein A represents a nitrogen atom or a CR 6 , R 1 represents a C2-C10 alkyl group having one or more halogen atoms, etc ., R 2 and R 3 represent independently of each other a hydrogen atom, etc., R 4 represents a C1-C6 chain hydrocarbon group optionally having one or more halogen atoms, R 5 represents a C1-C6 chain hydrocarbon group optionally having one or more halogen atoms, etc., R 6 represents a hydrogen atom, etc., n represents 0, 1, or 2, and p represents 0, 1, or 2, has an excellent efficacy for controlling harmful arthropods.
