In a storage section, there are stored special connecting waveform data for connecting between at least two notes to be generated in succession. The special connecting waveform data contain only a waveform of a succeeding-note region of a waveform connecting portion which is provided for a continuous transition between the at least two notes and which is divided into a preceding-note region and the succeeding-note region. When a connecting tone is to be generated for connecting between two notes in accordance with acquired performance information, a tone waveform connecting between waveforms of the two notes is generated using the special connecting waveform data. With such arrangements, the waveform data of the succeeding-note region are read out without waveform data of the preceding-note region being read out, so that it is possible to reduce a time required for transition from a preceding note to a succeeding note. Thus, in the connecting portion for continuously connecting between tones with no break therebetween, a tone can be synthesized with high quality without involving a tone generating delay in the succeeding note.