PROBLEM TO BE SOLVED: To provide an auxiliary device for improvement of sleep apnea syndrome, the device that facilitates setting in an oral cavity, eliminates the concern to swallow the device, and can secure a respiratory tract during sleep.SOLUTION: An auxiliary device for improvement of sleep apnea syndrome includes a tabular lip holding elastic body faced from a lower side to the oral cavity insert elastic body in the front-end side of a plate-like oral cavity insert elastic body with a bow shape in front view. The lip holding elastic body comprises a longitudinal length capable of being clamped with lips from front teeth in a plan view and a substantially rectangular shape having a horizontal width capable of being clamped with the lips. The oral cavity insert elastic body has a front end being the same as the front end of the lip holding elastic body in a plan view, and a rear end being the same as the longitudinal length before approaching the soft palate. The range faced with the lip holding elastic body has the same horizontal width as the lip holding elastic body, and has the horizontal width capable of coming into abutment with the buccal of a mouth floor in the rear from the faced range. A long projection part is provided from the front end to the rear end in the lower side of the oral cavity insert elastic body. A substantially U-shaped and grooved regulation section of tongue sagging prevention is extended in which a cross-sectional shape forms an opening in the rear from the central rear end of the projection part toward the lower part. Thus, the problem is solved by the device.SELECTED DRAWING: Figure 12【課題】口腔内へのセットが容易で、器具の飲み込む懸念がなく、就寝時に気道を確保できる睡眠時無呼吸症候群改善用補助器具を提供することを課題とする。【解決手段】正面視で弓形状で板状の口腔挿入弾性体の前端側に口腔挿入弾性体に対して下側から対向させた平板状の口唇挟持弾性体とを備え、口唇挟持弾性体は、平面視で、前歯から口唇で挟持できる前後方向の長さと、口唇で挟持可能な左右方向の幅を有する略四角形状からなり、口腔挿入弾性体は、平面視で、前端が口唇挟持弾性体の前端と同じで、後端が軟口蓋に近接するまでの前後方向の長さと、口唇挟持弾性体と対向させた範囲は前記口唇挟持弾性体と同じ左右方向の幅で、対向させた範囲より後方においては口腔底の頬側に当接可能な左右方向の幅を有し、口腔挿入弾性体の下側に前端部から後端部まで長尺
