PROBLEM TO BE SOLVED: To provide a reagent comprising a fewer components and facilitating to detect Legionella, and a method for more specifically and more variously detecting Legionella. SOLUTION: Disclosed is a method for genus-specifically amplifying a nucleic acid of the genus Legionella, wherein a method featured by that all species having possibility of belonging to the genus Legionella are amplified by using primers less than 7; a method for detecting one or more species of the genus Legionella based on the amplified nucleic acid; and a reagent kit for genus-specific amplification and species-specific detection of Legionella species comprising one set of primers less than 7 and at least one Legionella species-specific probe are provided. COPYRIGHT: (C)2007,JPO&INPIT