Many clinicians have long harboured an impression that there is a difference in the quality of the snoring sounds. Despite this awareness, there has been relatively little investigation of the acoustic quality and characteristics of the snoring sounds. We have recently studied the spectrographic analysis of the simulated snoring sounds. Simulated snoring sounds were made in various methods. Then we have found seven types of snoring sounds which were demonstrated by transnasal friberscopy and computerized tomogram scanner when he subject was simulating various sonring sounds. Spectrographic analysis was performed in seven different sounds. In cases of snoring sound made by only palattal flutter, periodic wide interval pulse showed. In cases of snoring sounds made by mainly nasal inspiration, second formant pattern between 4000Hz and 5000Hz showed. In cases of snoring sounds made by mainly mouth inspiration, second formant pattern between 500Hz and 1000Hz showed. In cases of snoring sounds made by hypopharyngeal vibration, strong formant pattern between 6000Hz and 8000Hz and strong noise components over 12000Hz showed.