PROBLEM TO BE SOLVED: To provide a bactericide having a higher bactericidal action than conventional macrolide antibiotics. SOLUTION: A Pseudomonas aeruginosa bactericide comprising a combination of a nitrogen-containing compound such as N-(piperidin-4-yl)dodecanoylamide and N-(pyrrolidin-3-yl)dodecanoylamide and a macrolide antibiotic. .. [Selection diagram] Figure 1【課題】従来のマクロライド系抗生物質よりも高い殺菌作用を有する殺菌剤の提供。【解決手段】N-(ピペリジン-4-イル)ドデカノイルアミド及びN-(ピロリジン-3-イル)ドデカノイルアミド等の含窒素化合物及びマクロライド系抗生物質を組み合わせてなる緑膿菌の殺菌剤。【選択図】図1