Abstract: The present invention provides a device which prevents loud snoring and apnea during sleep so as not to cause discomfort to a user as much as possible. Stoppers 4 such as belts or straps having predetermined elasticity are attached to both right and left sides of a lower jaw fitting piece 3 which fits the both sides of the lower jaw, the lower jaw 2 is pushed forward via the lower jaw fitting piece 3 by setting and hanging the stoppers 4 on the nose or head of the face side, whereby occurrence of apnea and loud snoring during sleep is prevented.