PURPOSE: To simplify the constitution by providing a means rewriting a code in response to a change signal inputted from the user to change a reproduction additional tone depending on the user and eliminating the need for a large scale signal processing circuit.

CONSTITUTION: In changing the scale of a reproduced tone into a scale higher by an n-semitone, an additonal tone code is read from a code input means l at first. Then a change signal increasing the n-semitone is inputted to a change signal input means 2 by the user, the signal is stored in the lst storage means 3 and outputted to a code rewrite means 4. The means 4 uses a high tone code conversion table for coding and when the coded additional tone code is sent, after the start part is detected, a vlaue adding (n) outputted from the means 3 is stored in the 2nd storage means 7. Succeedingly, the oeration is repeated and the rewritten code is given to a code decoding means 5, an additional tone generating circuit control means 6 and an additional tone generating circuit 8 to generate an additional tone higher by the (n) semitone. Thus, the reproduction additional tone is changed by the user and the constitution is simplified.