A singing voice synthesizing method and a singing voice synthesizing apparatus in which the singing voice is synthesized using performance data such as MIDI data. The performance data entered is analyzed as the musical information of the sound pitch, sound duration and the lyric (S2, S3). From the analyzed music information, the lyric is accorded to a string of sounds to form singing voice data (S5). Before delivering the singing voice data to a speech synthesizer, the sound range of the singing voice data is compared to the sound range of the speech synthesizer, and the key of the signing voice data and the performance data is changed so that the singing voice will be comprised within the sound range of the speech synthesizer (S9 to S12 and S14). A program, a recording medium and a robot apparatus, in which the singing voice is synthesized from performance data, are also disclosed.