A file server program that performs proper load distribution among a plurality of file servers. One of the plurality of file servers judges whether to perform a process in compliance with a request to manipulate a file on the basis of judgment conditions predefined for judging which process of processes performed by a cluster it should take charge of when it receives the request to manipulate a file of requests to manipulate a file sent to the plurality of file servers included in the cluster. If it judges that it must perform a process in compliance with the request to manipulate a file, it performs a process on a storage device which it manages in compliance with the request to manipulate a file.