A file conversion method, a data converter, and a file display system for extracting data handled by a limited capability display device from a plurality of pieces of data displayable on a standard display unit with a start and an end of each piece of data indicated by respective identifiers and for outputting the extracted data to the device in which the identifier is detected by reading the file and it is then determined whether identified data can be displayed on the limited capability display device. The data identified by the identifier is extracted and an output file, different than the file that was read, is created from the extracted data.