PURPOSE: To secure consistency on the whole of information representation and then to output only visual information or auditory information by providing an information converting means which converts 1st information between the visual information and auditory information into the other 2nd information and an output means which has an information output mode for outputting the 2nd information.

CONSTITUTION: The visual information consisting of image blocks, text blocks, etc., and the auditory information consisting of audio blocks, etc., are stored in a composite information file 11. Further, an auxiliary information file 12 has its inside divided into an auxiliary visual information file 12a containing visual information supporting the auditory information stored in the composite information file 11 and an auxiliary auditory information file 12b containing auditory information supporting the visual information stored in the composite information file 11. Even when only the visual information is outputted, this constitution outputs the auxiliary visual information instead of the auditory information or converts the auditory information into the visual information and outputs it.