PROBLEM TO BE SOLVED: To provide an intraoral mounting fixture for lip closing force measuring instruments being stably installable in the oral cavity and capable of correctly measuring lip closing force with little measurement error.SOLUTION: An intraoral mounting fixture 13 for lip closing force measuring instruments is a flat sheet to be installed between maxillomandibular central incisors and the lips. One surface of the flat sheet has a lip contact surface, the central part of which is gently convexly curved, and a step is provided at a substantially central part of the other surface of the flat sheet, where a lower side of the step is a maxillary central incisor contact surface coming into contact with the maxillary central incisor and a higher side is a mandibular central incisor contact surface coming into contact with the mandibular central incisor. A protrusion is formed at a vicinity of the central part of the maxillary central incisor contact surface so as to be fitted in the maxillary central incisor. A tensile force transmission part to which a string for transmitting tensile force in the lip contact surface direction is provided at the vicinity of the central part of the flat plate.
