Herein, I report a case of a temporomandibular joint herniation. A 77-year-old male patient presented with the complaint of developing tinnitus in his left ear when he bit into foods. On examination, I confirmed projection of the anterior wall of the external auditory canal during biting, with the projection retracting when the patient opened his mouth. Computed tomographic examination revealed a partial defect of the anterior wall of the bony external ear canal. I thought that this defect was caused by failure of the foramen of Huschke to close during development. The projecting anterior wall of the external auditory canal pressed on the eardrum, causing tinnitus of the left ear. This case underscores the need to bear in mind temporomandibular joint herniation as a cause of tinnitus.