9. The voice recognition system according to claim 2 , wherein (1) the length of the detected voice section and (3) the chronological order of the detected voice section are used in combination as the predetermined priority criterion, and the priority determining unit selects a plurality of detected voice sections that are continuous on the time series in reverse chronological order from a last detected voice section from among a plurality of detected voice sections contained in an inputted voice so that a sum of lengths of the selected detected voice sections falls within a predetermined range.
2. The voice recognition system according to claim 1 , wherein the priority determining unit uses as the predetermined priority criterion at least one selected from (1) a length of the detected voice section, (2) a power or an S/N ratio of the detected voice section, and (3) a chronological order of the detected voice section.