Sleep apnea syndrome is a very commom disease. This includes snoring, stuggling breath in sleep, pol-ycythemia, and hypertension. Most of them have had pathologic change of anatomy in upper airway called obstrctive sleep apnea syndrome, and other lokes central or mixed type is rare. However their causes are still unlnown. Apatient with obstructive sleep apnea syndrome need to receive operation at once, and anaesthesia become a highly difficult task, because of its sensitivity to anaesthetic agents. Even if small dosage of anase-thetics can rtsult in severe obstruction of upper airway. Therefore, to maintain a patent ariway in any stage of anaesia is very important.