A singing voice synthesizing method for synthesizing the singing voice from performance data is disclosed. The input performance data are analyzed as the musical information of the pitch and the length of sounds and the lyric (S2 and S3). A track as the subject of the lyric is selected from the analyzed musical information (S5). A note the singing voice is allocated to is selected from the track (S6). The length of the note is changed to suit to a song being sung (S7). The voice quality suited to the singing is selected based on e.g. the track name/sequence name (S8) and singing voice data is prepared (S9). The singing voice is generated based on the singing voice data (S10).