The present disclosure provides an agricultural and horticultural bactericide composition comprising at least one compound (A) which is selected from a nitrogenated heterocyclic compound having a specific structure including a compound represented by formula (1) or formula (2) and a salt of the nitrogenated heterocyclic compound and at least one compound (B) which is selected from a specific agrichemically active compound group. [In formula (1), X&rsquo；s independently represent a halogeno group or a C1-6 alkyl group； n is the number of X&rsquo；s and represents an integer of 0-6； X&rsquo； represents a halogeno group； and R1, R2 and R independently represent a C1-6 alkyl group or a hydroxy group.]
