Nitrogenated heterocyclic compound and agricultural or horticultural fungicide

An agricultural or horticultural fungicide contains as an active ingredient thereof at least one compound selected from the group consisting of nitrogenated heterocyclic compounds represented by formula (I) (wherein, R represents a group represented by CR 1 R 2 R 3 or a cyano group, R 1 to R 3 represent hydrogen atoms, alkyl groups or hydroxyl groups, or the like, X 1 represents a halogeno group or the like, m represents an integer of 0 to 5, X 2 represents a halogeno group or the like, n represents an integer of 0 to 3, B represents a carbon atom or a nitrogen atom, D represents a 5- to 7-membered hydrocarbon ring, and A 1 to A 4 represent carbon atoms or nitrogen atoms, provided that A 1 to A 4 do not all represent carbon atoms when B represents a carbon atom) and salts thereof.