In a digital signal processor to perform digital signal process with respect to a music signal and to suppress a signal level to a maximum value when the signal level over the maximum value of processable values is generated by the digital signal processor, a first level correcting device corrects the signal level by multiplying the signal level of the music signal by a correction coefficient so as to make the signal level of the music signal over the maximum value, and a second level correcting device corrects the signal level by multiplying the signal level of the music signal corrected by the first level correcting device by a reciprocal of the correction coefficient.