Even when a pitch cycle has a large fluctuation and the pitch cycle string changes abruptly, it possible to suppress the affect of the pitch cycle fluctuation and generate high-quality synthesized speech. A speech synthesis device generates a synthesized speech corresponding to an input text sentence according to an original speech waveform stored in original speech waveform information storage unit (25). The speech synthesis device includes pitch cycle correction unit (40) which extracts a fluctuation component of the pitch cycle of the original speech waveform which is obtained from original speech waveform information storage unit (25) in order to generate the synthesized speech and which corrects, based on the extracted fluctuation component, the pitch cycle of the synthesized speech obtained by analyzing the input text sentence. Pitch cycle correction unit (40) connects the pitch cycle waveform of the original speech waveform at the pitch cycle of the corrected synthesized speech.