The present invention relates to a pyridazinone compound of the formula (I): wherein R1 represents hydrogen, a C1-6 alkyl group, and the like, R2 represents halogen, a cyano group, a nitro group, a C1-6 alkoxy group, and the like, G represents hydrogen, and the like, Z represents halogen, a cyano group, a nitro group, a C1-6 alkyl group, and the like, and n represents an integer of 1-5 useful as an active ingredient in a herbicide and a noxious arthropod controlling agent.
