PROBLEM TO BE SOLVED: To provide a method capable of detecting existence of an organism, especially a noxious organism, by using a detection part having a simple structure.SOLUTION: Foam is generated physically by a method for agitating base materials by using a mixer or the like, or by a chemical action such as generation of carbon dioxide by mixing together a carbonate compound and an acidic compound, from a composition formed by blending one or more kinds of base materials for generating foam, and the foam is allowed to disappear by a biological action of an object organism. By utilizing such a phenomenon, existence of an organism, especially a noxious organism, can be detected.
