Pest insects, etc., are still causing serious damage to production of agricultural, horticultural, and other crops, and due to the reasons such as emergence of pest insects that are resistant to existing chemicals, etc., there is a need to develop new agricultural/horticultural insecticides. Provide, as a means for solving the problem, an oxazepine compound, or salt thereof, expressed by General Formula (I): [in the formula, R 1 , R 2 , R 3 and R 4 may be identical or different, representing a hydrogen atom, halogen atom, alkyl group, etc.； R 5 and R 6 may be identical or different, representing a hydrogen atom, alkyl group, or phenyl group, pyridyl group, etc., that may be substituted together with a carbon atom to which R 5 or R 6 is bonded； R 7 represents a hydrogen atom, alkyl group, alkynyl group, cyano alkyl group, alkoxy alkyl group, etc.； Y represents an oxygen atom, S, NH, etc.； Y 1 represents a C=O, C=S, CH 2 group, etc.； A represents a CH group, etc.； and m represents 0 or 1], as well as an agricultural/horticultural insecticide using such oxazepine compound or salt thereof as its active ingredient, and method for using the same.
