Disuse atrophy of various organs related to swallowing functions is one of the causes of swallowing disorders. In the present study, a system to measure swallowing frequency in a nonrestrictive manner over a long period of time was developed. In the present method, a throat microphone is attached to the neck region to record oral sounds. The reliability of the method is confirmed by recognizing 86% of swallowing sounds. Since the interval of swallowing in a complete rest is getting longer according to aging, the swallowing function is possibly getting weaker.