PURPOSE: To eliminate the overrun and the underrun of audio data even when the data are stored on a disk device by processing an input source signal and outputting it to the device of an audio interface while storing the source signal on the disk device when a computer in which the audio interface is built performs audio signal processing.

CONSTITUTION: The source signal inputted from an audio input port 17 is converted by A/D 19 into digital audio data, which are transferred to DSP 11 and processed while stored on the audio disk device 15 through a multi-port buffer 13. The processed audio data while stored on the audio disk device 15, are converted by D/A 23 into an analog audio signal through the multi-port buffer 13 and outputted to an audio output port 21.