1. A speech recognition dictionary creating support device comprising: a speech data storage section storing speech data; a prosodic information extracting section extracting prosodic information including at least a speech power value from the speech data; a speech data dividing section extracting an utterance section having a period with a power value equal to or larger than a predetermined threshold value lasting a preset time or longer from the speech data based on the prosodic information, and dividing the utterance section into sections, each of which has a power value equal to or lamer than a predetermined threshold value continuing for a given time or longer, to generate divided speech data; a phoneme sequence acquiring section executing a phoneme recognition process on the divided speech data to acquire phoneme sequence data for each divided speech data; a clustering section executing a clustering process on the phoneme sequence data to generate clusters each of which is a set of classified phoneme sequence data; an evaluation value calculating section calculating an evaluation value for each of the clusters based on the prosodic information for the divided speech data corresponding to the phoneme sequence data constituting the cluster; a candidate cluster selecting section selecting clusters for which the evaluation value is equal to or larger than a given value, as candidate clusters; and a listening target data selecting section determining one of the phoneme sequence data from the phoneme sequence data constituting the cluster for each of the candidate clusters to be a representative phoneme sequence and selecting the divided speech data corresponding to the representative phoneme sequence, as listening target speech data, and wherein the evaluation value calculating section includes dictionary data for a morpheme analysis process, and extracts a phrase classified as a predetermined word class from the dictionary data, calculates an appearance probability, in the extracted phrase, of a common phoneme subsequence constituting in the cluster, and calculates the evaluation value for the cluster based on the appearance probability.
6. The speech recognition dictionary creating support device according to claim 1 , wherein the listening target data selecting section determines phoneme sequence data with a largest number of corresponding divided phoneme data in the candidate cluster to be the representative phoneme sequence.