The present invention relates to a storage system including a de-duplicate function and a full-text search function or the like, and reduces an amount of index information about full-test search to save storage resource. In this system, a storage apparatus includes a processing unit for de-duplicating a plurality of files having the same content regarding a file group of data inputted/outputted through a host apparatus. A full-text search processing server performs a full-text search processing to the file group and includes a processing unit for causing the full-text search processing to correspond to de-duplicate. An index information creation processing performed to a plurality of target files having the same content by the full-text search processing unit is inhibited according to a status of de-duplicate to the file group by the processing unit. Thereby, the amount of index information can be reduced.