PROBLEM TO BE SOLVED: To provide a dentition mouthpiece which effectively maintains the airway by stably holding the tongue.
SOLUTION: The dentition mouthpiece 20 is provided with an upper side recessed groove part 22 to be engaged with a maxillary dentition and a lower side recessed groove part 24 to be engaged with a mandibular dentition. On the inner wall of the dentition mouthpiece 20, cavities 44 for holding the tongue which holds the side faces of the tongue at positions in the height direction nearly in the middle of the bottom of the upper side recessed groove part 22 and that of the lower side recessed groove part 24 are formed. Extension parts 28 at the inside part of the saddle-formed walls of the lower side recessed groove part 24 are extended to the boundaries of the movable parts and the unmovable parts of the gum parts 36 of the madibular dentition. A belt-shaped palate support 26 connects the inside wall part of the saddle-formed wall forming the upper side recessed groove part 22 corresponding to the left molars part 32 of maxillary dentition and that forming the upper side recessed groove part 22 corresponding to a right molars part 34, and its upper face is formed to have a shape along a soft palate within the oral cavity.