18. The Hidden Markov Model generation system according to claim 11 , comprising a model-to-be-used selection section that selects, from the scheduled-to-be-used model group, Hidden Markov Models to be used for generating filler models, as models to be used, and the filler model generation section generates Hidden Markov Models to be used as filler models by the given speech recognition system based on the Hidden Markov Model group selected as the models to be used.
20. The Hidden Markov Model generation system according to claim 18 , wherein the model-to-be-used selection section detects elements necessary for speech recognition of input text data, and selects Hidden Markov Models of elements other than the detected elements as the models to be used.