To provide a supporting device 2 for a top board 3, which enables a corner desk 1 to be used for various installation locations, uses, etc., by imparting many variations to the utilization form of the corner desk 1.

The supporting device 2 makes the top board 3 supported by a pair of leg devices 4 and 4 and a modesty panel device 5 coupled detachably between the leg devices 4 and 4. The panel device 5 is composed of respective two of modesty panel parts 20 and 21 of two types different in cross-direction length, and a leg column 22, an intermediate coupling body 23 and a leg body 52, which serve as coupling means. The respective panel parts 20 and 21 are coupled together via the respective coupling means for the purpose of making the panel device 5 constituted in such a manner as to be changeable between installation in an approximate W-shape and the installation in an approximate L-shape when seen from a plan.