PURPOSE: To give an effect sound match to musical performance information such as key depressing information and key information without increasing the circuit scale by controlling the output levels of musical sound signals according to the musical performance information, and giving different effects to the musical sound signals and putting them together.

CONSTITUTION: The musical sound signal outputted from a musical sound signal generation part 81 is multiplied by coefficients A and B through multipliers 82 and 83, whose results are inputted to accumulators 84 and 85. When the strength of a touch is small in this case, the output level of the musical sound signal from the multiplier 82 is smaller and the output level of the musical sound signal from the multiplier 83 is larger. When the strength of the touch is large, on the other hand, the output level of the musical sound signal from the multiplier 82 is larger and the output level of the musical sound signal from the multiplier 83 is smaller. Then a 1st effect granting unit 91 and a 2nd effect granting unit 92 execute an effect program stored in a memory to give the effects to the input musical sound signal.