This device is used to maintain the patient's mouth during oral surgery or examinations, prevent unintended biting, or facilitate the insertion and fixation of endotracheal tubes. It is an auxiliary instrument for maintaining the patient's mouth during surgery or examinations, consisting of a fixation device, a sliding rail, a skin isolation pad, and an adjustable neck strap. The fixation device and sliding rail are made of polypropylene, the skin isolation pad is made of hydrocolloid material, and the adjustable strap is made of nylon webbing.