To conduct effective filtering processing by a filter coefficient of a high degree of freedom, even when a memory capacity of a compute body is not sufficient, or even when a noisy tone color is prepared.

A CPU 1 determines the presence of an input of a set value from an operator 7 when executing setting processing according to a musical sound control processing program of a ROM 2, and the input set value is stored in a register T of a RAM 3 when the input exists. Then, a filter coefficient for only a value at the time when '1' expressed by binary numbers is bit-shifted to the left side by the set value of the register T is prepared.