The present invention is to provide an oxopyrazine derivative having an excellent herbicidal activity and besides exhibiting high safety for useful crops and the like , or a salt thereof, and a herbicide containing the same. The present invention relates to an oxopyrazine derivative represented by formula [I]: wherein X 1 represents an oxygen atom or a sulfur atom； X 2 represents CH or N(O) m ； m represents an integer of 0 or 1； R 1 represents a hydrogen atom, a C 1 -C 12 alkyl group and the like； R 2 represents a halogen atom, a cyano group and the like； R 3 is a hydroxyl group, a halogen atom and the like； A 1 represents C(R 4 R 5 ) ； A 2 represents C(R 6 R 7 ) or C=O； A 3 represents C(R 8 R 9 )； R 4 to R 9 represent a hydrogen atom or an alkyl group, or a salt thereof, and a herbicide containing these compounds.
