Abstract: Provided is an assistant apparatus for oral treatment including dental treatment and a unit chair equipped with the same. The assistant apparatus includes an oral cavity insertion member positioned in the oral cavity in front of the uvula of a patient, or preferably, on the soft palate, such that washing liquid or saliva is prevented from entering a patient's throat during oral treatment. Therefore, it is possible to prevent patient discomfort and interruption of treatment. Further, medical instruments/components are prevented from entering the throat and injuring the pharynx.