Privacy information of a user is protected without hampering convenience when such user is to process a file in an online file storage. Provided is a file sharing system including at least one or more information processing units and a storage apparatus connected to the at least one or more information processing units via the Internet, and for storing files from the at least one or more information processing units in the storage apparatus and sharing the stored files with the at least one or more information processing units. The information processing unit includes a file creation unit for separating, when creating a file in the storage apparatus, privacy information that identifies a user creating the file from information required for creating the file in the storage apparatus, and creating the file in the storage apparatus by using information obtained by converting the separated privacy information.