The present invention relates to a pyridazinone compound of the formula (I):wherein R1represents hydrogen, a C1-6alkyl group, and the like, R2represents halogen, a cyano group, a nitro group, a C1-6alkoxy group, and the like, G represents hydrogen, and the like, Z represents halogen, a cyano group, a nitro group, a C1-6alkyl group, and the like, and n represents an integer of 1-5 useful as an active ingredient in a herbicideand a noxious arthropod controlling agent.本發明係關於用作為除草劑和有害節肢動物防制劑中之活性成分的式(I)之噠嗪酮化合物：其中R1代表氫、C1-6烷基基團等，R2代表鹵素、氰基基團、硝基基團、C1-6烷氧基基團等，G代表氫等，Z代表鹵素、氰基基團、硝基基團、C1-6烷基基團等，且n代表1-5之整數。
