To stably hold and fix a patient's head liable to move, regarding medical and dental diagnosis and treatment for a patient involving a danger of moving his/her head, such as a handicapped person, an infant or the like.

An operator's forearm support projection plate 4 is extended from one side of a medical and dental headrest 2. The operator places his/her forearm of one hand to hold a patient's jaw on the forearm support projection plate 4, thereby causing the forearm support projection plate 4 to bear the patient's moving resistance force acting on the forearm. Thus, the operator can hold and fix the patient's jaw by his/her one hand stably over a long time. At the same time, the other hand can be used for accurately and efficiently diagnosing and treating the patient.