To provide a dental treatment chair which an advanced age person or a physically handicapped person can easily get on/off.

This dental treatment chair has a seat 21 on a contour seat 13, and the seat 21 is normally placed under a state shown in Figure (A). A patient sits on the treatment chair 10 under this state, and an operator vertically moves or tilts/raises the chair, and performs a treatment under a state wherein the treatment for the patient can be easily performed. When the patient gets on/off from the treatment chair 10, the seat part is slid in the direction of arrow A (lateral direction) as shown in Figure 1 (B), and the seat 21 is extended sideways from the treatment chair 10. Under that state, or by rotating the seat 21 in the B direction (the direction wherein an armrest 22 separates from the backrest) when required, a state wherein the patient can easily get off from the seat is presented.