A speech synthesizing system using a redundancy-reduced waveform database is disclosed. Each waveform of a sample set of voice segments necessary and sufficient for speech synthesis is divided into pitch waveforms, which are classified into groups of pitch waveforms closely similar to one another. One of the pitch waveforms of each group is selected as a representative of the group and is given a pitch waveform ID. The waveform database at least comprises a pitch waveform pointer table each record of which comprises a voice segment ID of each of the voice segments and pitch waveform IDs the pitch waveforms of which, when combined in the listed order, constitute a waveform identified by the voice segment ID and a pitch waveform table of pitch waveform IDs and corresponding pitch waveforms. This enables the waveform database size to be reduced. For each of pitch waveforms the database lacks, one of the pitch waveform IDs adjacent to the lacking pitch waveform ID in the pitch waveform pointer table is used without deforming the pitch waveform.