1. A speech recognition apparatus comprising: a word search unit that performs a word search based on an acoustic distance between a phonetic model and a feature amount of input speech and a phoneme of a word in a language model including the phoneme and a prosodic label of the word, outputs a word hypothesis and a first score representing likelihood of the word hypothesis as a word search result, and when assuming that a recognition result of the input speech is the word hypothesis, outputs a prosodic interval and a prosodic label of the prosodic interval in the input speech; a prosodic recognition unit that outputs a second score representing likelihood of the prosodic label output from said word search unit, based on one of feature amounts of the input speech corresponding to the prosodic interval output from said word search unit; and a rescore unit that corrects the first score of the word hypothesis output from said word search unit using the second score output from said prosodic recognition unit, wherein the prosodic label is one of a tone label and an accent type, and the prosodic interval is one of a vowel interval and an accent interval.