Abstract: There is provided a firmware updating technique for which consumed memory and writing time are small for devices subject to a firmware update, for which the distributed update size is small, and which is performed via a broadcast network. To this end, assuming that the latest firmware version is N, there is provided a means that extracts differences between firmware of version j?i and firmware of version i (j?1?j differences) for j=2 to N, and that distributes these differences together via the broadcast network. With respect to a device subject to an update comprising firmware of version i, there is provided a means that saves, of the distributed j?1?j differences (where 2?j?N), only the differences for which j<i in a storage area, generates an i?N difference based on the saved j?1?j differences (where i?j?N), and updates the firmware in flash memory based on the content of the i?N difference (see FIG. 1).