PURPOSE: To classify inputted voices for every speaker without using a dictionary, to execute various processes including retrieval and presentation to the classified inputted voices and to execute classification and other processes to general acoustic signals based on a prescribed reference.

CONSTITUTION: An acoustic feature levels 103 or an acoustic signal 101 extracted by an acoustic feature level extracting means 102 is stored for every generating condition of the signal 101 by a sorting means 104. The levels 103 is classified by a classifying means 105 employing the classification for every generating condition of the signal 101 as reference. As a result, the levels 103 as well as the signal 101 are automatically classified in an independent condition with respect to the generating condition of the signal 101 without using a specific dictionary, etc.