Provided are 2-pyridone derivatives which have excellent herbicidal activity and exhibit high safety to useful crops and so on salts thereof and herbicides containing same. In more detail, 2-pyridone derivatives represented by general formula [I] or agrochemically acceptable salts thereof, and herbicides containing these compounds are provided. In general formula [I], X1 is an oxygen atom or a sulfur atom X2, X3, and X4 are each CH or N(O)m m is an integer of 0 or 1 R1 is a hydrogen atom, a C1-12 alkyl group, or the like R2 is a halogen atom, a cyano group, or the like n is an integer of 0 to 4 R3 is a hydroxyl group, a halogen atom, or the like A1 is C(R11R12) A2 is C(R13R14) or C=O A3 is C(R15R16) and R11, R12, R13, R14, R15, and R16 are each independently a hydrogen atom or a C1-6 alkyl group.
