A video server and a file management method which can erase an unnecessary program data file promptly are provided. Video server S divides processing of management of files performed by one frame into 11 sections, assigns five sections to playing process, assigns five sections to recording process and assigns one section to erasing process and performs processing of the file management. Server S supervises the file processing under executing. When a number of sections which perform the playing process or a number of sections which perform recording process is smaller than 5 and there is a demand of the erasing process for more than 2 files, server S assigns the section which is not used to the erasing process and unnecessary files are erased.