A proposed file delete method is a method used by a computer or a file processing device performing a process of outputting to a device driver a directive corresponding to a directive to delete a file satisfying a predetermined condition from an application, and includes: a step of obtaining in primary storage from an actual data area in secondary storage the directory entry information in a directory storing a file to be deleted; a step of adding in the primary storage a delete mark to the file in the obtained directory entry when the file in the obtained directory entry satisfies the predetermined condition; a step of writing a result of the delete mark adding process to a corresponding portion of the actual data area in the secondary storage; and a step of freeing FAT information stored in the secondary storage corresponding to the delete mark added file.