An office chair including a base, a seat, a chair column that extends in the vertical direction between the base and the seat, and a backrest, further comprising an electric drive unit that comprises an electric motor and a change gear, the change gear being designed to input the rotational force of the electric motor into a first adjustment device for adjusting a seat height of the seat and converting said force in a second adjustment device for adjusting a tilt of the seat or the backrest.