A file search system in which first and second file search servers (5, 1), a file server and a client are communicably interconnected via a wired or wireless communications line, the first file search server comprising: index 1 creation means adapted to create, from files subject to search on a storage device connected to the file server, and store in an index 1 file index 1 records including at least file names (211, 221b), file paths (212, 221C), access authority and keywords; wherein the second file search server comprises: index 2 creation means adapted to create, from files subject to search, and store in an index 2 file index 2 records comprising system metadata including at least file names (211, 221b) and file paths (212, 221c), standard metadata and user-defined metadata; means adapted to analyze, upon receiving a search request from the client, a conditional search expression included in the search request, and adapted to determine whether or not to perform a metadata search based on the conditional search expression; metadata search means adapted to select, if it is determined that a metadata search is to be performed and from the index 2 records of the index 2 file, metadata matching records that match a condition based on the conditional search expression; means adapted to determine, after a metadata search is performed or if it is determined that no metadata search is to be performed, whether or not to perform a full-text search, the full-text search being based on the conditional search expression; full-text search means adapted to perform a full-text search with respect to the index 1 file, if it is determined that a full-text search is to be performed, by referencing the keywords based on the conditional search expression and the metadata matching records; means adapted to transmit to the client, if a full-text search is executed, each data item of an index 1 record that is a keyword matching record that is retrieved, and to transmit to the client, if it is determined that no full-text search is to be performed, the metadata matching records; characterized by: means adapted to compare a number of metadata matching records retrieved through the metadata search with a pre-defined number in cases where both the metadata search and the full-text search are to be performed; and means for receiving a confirmation result from the client as to whether or not the full-text search is to be executed, in cases where the number of records in the metadata matching record is larger than the pre-defined number; and wherein said first and second file search servers (5, 1) are either the same file search server or two different communicably interconnected file search servers. index 2 creation means adapted to create, from files subject to search, and store in an index 2 file index 2 records comprising system metadata including at least file names (211, 221b) and file paths (212, 221c), standard metadata and user-defined metadata; means adapted to analyze, upon receiving a search request from the client, a conditional search expression included in the search request, and adapted to determine whether or not to perform a metadata search based on the conditional search expression; metadata search means adapted to select, if it is determined that a metadata search is to be performed and from the index 2 records of the index 2 file, metadata matching records that match a condition based on the conditional search expression; means adapted to determine, after a metadata search is performed or if it is determined that no metadata search is to be performed, whether or not to perform a full-text search, the full-text search being based on the conditional search expression; full-text search means adapted to perform a full-text search with respect to the index 1 file, if it is determined that a full-text search is to be performed, by referencing the keywords based on the conditional search expression and the metadata matching records; means adapted to transmit to the client, if a full-text search is executed, each data item of an index 1 record that is a keyword matching record that is retrieved, and to transmit to the client, if it is determined that no full-text search is to be performed, the metadata matching records; characterized by: means adapted to compare a number of metadata matching records retrieved through the metadata search with a pre-defined number in cases where both the metadata search and the full-text search are to be performed; and means for receiving a confirmation result from the client as to whether or not the full-text search is to be executed, in cases where the number of records in the metadata matching record is larger than the pre-defined number; and