1. A speech recognition apparatus comprising: a sound information acquiring unit that acquires sound information; a unit segment dividing unit that divides the sound information into plural unit segments; a segment information acquiring unit that acquires segment information that indicates a feature of each unit segment; an utterance segment determining unit that determines whether the target segment is an utterance segment corresponding to an utterance of a person or not; a segment relation value calculating unit that calculates a segment relation value that indicates a relative feature of a target segment which is a unit segment to be processed with respect to an adjacent segment which is a unit segment adjacent to the target segment, based on segment information of the target segment and segment information of the adjacent segment among the segment information when the target segment is determined to be the utterance segment; a recognition candidate storing unit that stores recognition candidates that are targets of speech recognition; and a recognition result selecting unit that selects a recognition result from the recognition candidates stored in the recognition candidate storing unit utilizing the segment relation value.