a target parameter generation unit operable to generate target parameters on an element-by-element basis from information containing at least phonetic symbols, the target parameters being a parameter group through which speech can be synthesized;

a speech element database which stores, on an element-by-element basis, pre-recorded speech as speech elements that are made up of a parameter group in the same format as the target parameters;

an element selection unit operable to select, from said speech element database, a speech element that corresponds to the target parameters;

a parameter group synthesis unit operable to synthesize the parameter group of the target parameters and the parameter group of the speech element by finding the similarity per dimension of the target parameters and the speech element, selecting, based on the similarity per dimension, the speech element in the case where the target parameters and the speech element are judged as being similar and select, based on the similarity per dimension, the target parameters in the case where the target parameters and the speech element are judged as not being similar, and integrating the parameter groups on an element-by-element basis; and

a waveform generation unit operable to generate a synthetic speech waveform based on the synthesized parameter groups.