To enable anyone to easily and simply adjust the height position of a top plate by automating the height adjustment of the top plate.

This system desk S1 is provided with the top plate 1, a supporting leg part 20 and an adjustment device 14 for adjusting the height of the top plate 1. The top plate 1 is provided with respectively independently freely vertically movable first top plate part 11 and second top plate part 12. The adjustment device 14 is provided with an electric motor 25, a pair of feed screw mechanisms 13 provided on both end parts of the top plate parts 11 and 12 and a transmission means 26 for synchronously operating the pair of the feed screw mechanisms 13. Then, by the electric motor 25, the height of the respective top plate parts 11 and 12 is adjusted through a transmission member and the feed screw mechanisms 13.