Abstract: The present invention relates to a speech synthesis apparatus for generating an emotionally expressive synthesized voice. The emotionally expressive synthesized voice can be generated by generating a synthesized voice with a tone being changed in accordance with an emotional state. A parameter generator 43 generates transform parameters and synthesis control parameters on the basis of state information indicating the emotional state of a pet robot. A data transformer 44 transforms the frequency characteristics of phonemic unit data as speech information. A waveform generator 42 obtains necessary phonemic unit data on the basis of phoneme information included in a text analysis result, processes and connects the phonemic unit data with one another on the basis of prosody data and the synthesis control parameters, and generates synthesized voice data with the corresponding prosody and tone. The present invention is applicable to robots for outputting synthesized voices.