An audio input/output control apparatus, in which the speed difference between writing speed in writing audio data to a ring buffer and reading speed in reading out the audio data under a constant speed is calculated. When a read-address is forcibly changed according to the speed difference, between the signal level of the audio data corresponding to a read-address before the change and the signal level of the audio data corresponding to a read-address after the change, an address position at which the signal level change is less than a predetermined value is determined as a read-address after the change. So, the amount of signal processing can be significantly reduced, and the quality of audio data can be maintained.