PYRIDAZINE COMPOUND AND HERBICIDE

A compound represented by formula (I) or a salt thereof, and a herbicide containing at least one selected from the group consisting of the compounds described above as an active ingredient. In formula (I), R1 represents a substituted or unsubstituted C1 to C6 alkyl group, or the like, R2 represents H, a substituted or unsubstituted C1 to C6 alkyl group, or the like, R3 represents H, a substituted or unsubstituted C1 to C6 alkyl group, or the like, R4 represents a halogeno group, a substituted or unsubstituted C1 to C6 alkyl group, or the like, R5 represents H or a halogeno group, R6 represents H or a halogeno group, A represents a substituted or unsubstituted C1 to C4 alkylene group, a substituted or unsubstituted C2 to C3 alkenylene group, or a C1 to C2 alkyleneoxy C1 to C2 alkylene group, X1 represents O or a sulfonyl group, X2 represents O, a sulfenyl group, or the like, m represents 0 or 1, n represents 0 or 1, and m + n = 1 or 2, and when A is a substituted or unsubstituted methylene group, m + n = 2.