To provide a dental treatment unit for which, in details, a work table is composed of a work table main body and a tray slidable in a horizontal direction at the upper part of the work table main body and the tray can be positioned above the chest part of a patient at the time of dental treatment.

When a dental treatment chair 1 is turned to a brought-down (lying) state and the dental treatment is to be performed from the back side (behind) of a patient, the tray 22 provided on the work table main body 21 is slid in the horizontal direction (direction of arrow A) and the tray is arranged above the chest part of the patient. Thus, the work of taking and returning equipment for the dental treatment mounted on the tray 22 is facilitated and dental treatment work is very easily performed. Also, since recessed parts 2a and 2b or the like for housing the equipment for the dental treatment are provided on the work table main body 21, usually nothing is placed on the tray 22, and it is easy to clean and can be maintained in a clean state.