To prevent the time that is taken for information transfer from increasing when an amount of information to be transferred increases because there is a limitation to the shortening of a time that is taken to compress and expand information.

When a dividing part 13a which divides information into byte data streams of each prescribed bytes is provided, and the information is transferred from a device 10a to a device 10b, first, the part 13 divides information to be transferred into byte data streams of every prescribed bytes, a compressing part 11a mutually and parallelly compresses divided information in each byte data stream, a mixing part 15a adds an identifier to each byte data stream that is divided and compressed, mixes them and transfers them as one information string. After that, a distributing part 16b in the device 10b distributes byte data streams from the transferred information streams based on the identifier of each byte data stream, an expanding part 12b mutually and parallelly expands the transferred information in every byte data stream, thereby restoring the transferred information.