Proposed are a file storage apparatus and an access control method capable of facilitating the setting and change of an access right of a user for accessing a file.A first account which only authorizes referral of all files and a second account which authorizes referral and editing of all files are defined in advance as accounts in a file system, and if a workspace unit receives an access request from a client for accessing a file and the access right in the workspace of the user for accessing the target file of the access request and the access right in the file system are different, the workspace unit requests the file system unit to perform the access processing to the file upon switching the account of the user to the first or second account.