Abstract: Waveform generating section 100 generates a waveform, and waveform collecting sections 200-1 to 200-3 collect the waveform generated by waveform generating section 100. Waveform comparing section 300 compares waveforms collected by waveform collecting sections 200-1 to 200-3 with each other. Group generating section 400 groups waveform collecting sections 200-1 to 200-3, which collected identical waveforms, into one group as a result of comparison.

Abstract: Provided is an index making device for lightening a load on a network and an information-providing server. The index making device (2) comprises information acquiring means (201) for acquiring the reference information, which is acquired by a terminal device (5) demanding an information providing device (4) for sending specific information via a network (1), and the reference history information which contains the reference target information for discriminating the place where that reference information is stored, and index making means (202) for making an index for retrieving the reference information from the reference history information and the reference information, which were acquired by that information acquiring means.