1. A speech recognition apparatus comprising: a speech recogaition unit implementing a speech recognition process by using acoustic models about a set of phonemes and language models about a chain probability of a word group consisting of the set of phonemes; and a model learning unit that (1) classifies speaking section included in speech data according to lengths of the speaking sections, (2) classifies detailed data parts corresponding to predetermined parts in each of the classified speaking sections according to start time of the predetermined parts, and (3) learns the acoustic models and the language models by using the classified detailed data parts specified both of the lengths of the speaking sections and the start time of the predetermined parts.