In a typical musical tone producing device of a full waveshape readout type, a full waveshape of a musical tone to be produced from the start to the end of sounding or a rise portion and a part of the waveshape following the rise portion of the musical tone is stored in a waveshape memory, and the musical tone is formed by reading out the waveshape from the waveform memory once, or reading out the rise portion once and thereafter reading out the partial waveshape repeatedly. A digital filter is introduced following the waveshape memory in this tone producing device. The filter characteristics are determined in accordance with a tone color change parameter such as the key touch or the tone pitch of the musical tone, thereby realizing a tone color change of the musical tone. Further, in order to realize timewise change of tone color of the musical tone, the circuit which has the tone color change parameter vary with time is proposed.