Objective: Some patients with jaw anamorphosis symptom who underwent orthognathic surgery for lower jaw. By conducting auditory tube function tests before and after orthognathic surgery for the lower jaw, studied were the pathophysiology, incidence, causes and treatment of auditory tube dysfunction occurring following orthognathic surgery for lower jaw. Method: Regarding auditory tube function tests, the impedance test, or tympanometry, was sonotubometry, and TTAG were conducted. Patients whose auditory tubes conducted dysfunction was found to be aggravated were observed with daily TM testing until the function recovered to the preoperative level. Results: 1) Postoperative auditory tube dysfunction was noted subjectively in 18.3% and determined by TM in 60.4%. Lowered auditory tube function was found by TM at a high rate following orthognathic surgery for the lower jaw. Approximately 30% of patients with TM aggravation complained of ear symptoms. Among subjective ear symptoms, the most prevalent was a feeling of ear obstruction, and the second most prevalent was dysacusis. 2) It was suggested that TTAG could be a useful test for prediction of postoperative TM aggravation. Conclusion: Postoperative auditory tube dysfunction correlated with preoperative TTAG values, indicating that TTAG was a useful test for the prediction of TM aggravation. There was no correlation between postoperative auditory tube dysfunction and sonotubometry values. Postoperative auditory tube dysfunction recovered spontaneously in an average of 3.48 days without provision of ventilation treatment.