PROBLEM TO BE SOLVED: To provide an agriculture and horticulture fungicidal composition capable of stabilizing an agrochemical effect of an agrochemical fungicide.SOLUTION: This agriculture and horticulture fungicidal composition contains (A) one or more of agriculture and horticulture fungicides selected from a group consisting of a benzimidazole-based fungicide, a guanidine-based fungicide, an organic sulfur-based fungicide, an anilinopyrimidine-based fungicide, a triazole-based fungicide, an organochlorine fungicide, and an organocoppoer fungicide, (B) a dialkyl sulfosuccinate, and (C) a polyoxyethylene C11-C15 alkyl ether, wherein the content ratio is (A):(B):(C)=1-70:1:1-4.【課題】農薬殺菌剤の農薬効果を安定化させる農園芸用殺菌剤組成物を課題とする。【解決手段】(A)ベンゾイミダゾール系殺菌剤、グアニジン系殺菌剤、有機硫黄系殺菌剤、アニリノピリミジン系殺菌剤、トリアゾール系殺菌剤、有機塩素系殺菌剤、有機銅系殺菌剤からなる群より選ばれる1種以上の農園芸用殺菌剤、(B)ジアルキルスルホコハク酸塩、(C)ポリオキシエチレンC11~C15アルキルエーテル、であり、(A):(B):(C)=1~70:1:1~4の含有量比率で含有する農園芸用殺菌剤組成物。【選択図】なし