11. A speech recognition device for improving speech recognition performance, said speech recognition device comprising: a speech data generation section for identifying a start position of a speech region of speech data for which speech recognition is to be performed and generating, from said speech data for which speech recognition is to be performed, a plurality of pieces of speech data including said speech region and a varying period of a preceding non-speech region, where start positions of non-speech regions differ for the plurality of pieces of speech data; a speech recognition engine, for performing speech recognition on the speech data, provided for each of a plurality of pieces of speech data whose start positions of non-speech regions differ in order to obtain a plurality of recognized results; and a recognized result section, for selecting and providing as an output a most numerous recognized result from among the plurality of obtained recognized results; wherein said speech data generation section generates, from speech data for which speech recognition is to be performed, a plurality of pieces of speech data whose start positions of non-speech regions differ, by sequentially shifting the start position of said non-speech region from the start position of the speech region back to a position preceding by a predetermined time.
11. A speech recognition device for improving speech recognition performance, said speech recognition device comprising: a speech data generation section for identifying a start position of a speech region of speech data for which speech recognition is to be performed and generating, from said speech data for which speech recognition is to be performed, a plurality of pieces of speech data including said speech region and a varying period of a preceding non-speech region, where start positions of non-speech regions differ for the plurality of pieces of speech data; a speech recognition engine, for performing speech recognition on the speech data, provided for each of a plurality of pieces of speech data whose start positions of non-speech regions differ in order to obtain a plurality of recognized results; and a recognized result section, for selecting and providing as an output a most numerous recognized result from among the plurality of obtained recognized results; wherein said speech data generation section generates, from speech data for which speech recognition is to be performed, a plurality of pieces of speech data whose start positions of non-speech regions differ, by sequentially shifting the start position of said non-speech region from the start position of the speech region back to a position preceding by a predetermined time. 12. A speech recognition device according to claim 11 , further comprising: an analog to digital converter for converting an input speech signal from analog to digital at a predetermined sampling time interval; and a speech buffer for storing the converted speech data in an order of sampling, wherein said speech data generation section generates a plurality of pieces of speech data whose start positions of non-speech regions differ, by changing a reading position from the speech buffer, and provides the speech data to each speech recognition engine.