To provide an odontotherapeutic unit which can be easily changed over to the right and left simply by rotationally moving an arm for an instrument holder for an assistant and laterally moving a worktable for an operator.

The odontotherapeutic unit has an odontotherapeutic chair 1, a spittoon 2 containing a chair lifting device for vertically moving the chair 1 in the side part of the chair 1, an odontotherapeutic worktable 4 for the operator and the instrument holder 5 for the assistant. The supporting arm 8 of the instrument holder 5 for the assistant is rotatably attached to a base portion 7 of the chair in the lower part of approximately the central part of the chair 1 and the worktable 4 for the operator is connected to the base portion 7 through a flexible hose 9 and is made movable by castors 10.