An information search system for searching detection algorithm information of spectral data necessary for determining a target event from a photographed subject includes a first relational database configured to store, in advance, a first relevance index having at least three levels between each target event of the subject and the detection algorithm information, a target event input unit configured to receive input information regarding a target event of the subject to be newly determined, and a search unit configured to search at least one piece of detection algorithm information on the basis of information regarding the target event received by the target event input unit by referencing the first relevance index stored in the first relational database.