To provide synthesized voice to a user by means of easily understandable sentence data.

An analysis processing section 102 identifies words of a sentence being segmented by a sentence inputting section 101 and conducts various processes for reading and accenting. A repetition detecting section 103 detects a homonym. When the section 103 detects a homonym in a sentence which is an object of analysis, a replacement processing section 104 retrieves a synonym of the homonym from a synonym dictionary (a database 109) and replaces the homonym by the found synonym. When the above process is completed for a sentence, a waveform generating section 105 generates data for voice waveforms from the analyzed reading and accents by referring to a piece dictionary (a database 110) and a voice output section 106 outputs the generated voice waveforms data as voice.