To use a single kind of cooking work plate corresponding to the top plates of two different thickness by forming a restraining flange part at an edge part and forming a raised disk-like part at the whole of a center part excepting for the restraining flange part in the cooking work plate restrained on the top of a sink to be freely movable.

The cooking work plate A which is used by restraining to a guiding part on the top of the sink by the restraining flange part 1 to be freely movable forms the part 1 at the whole peripheral part and forms the raised disk-like part 2 at the enter part except for the part 1. At the time of applying this plate A to a sink with top plates 4 and 5, the plate A can cope with the thickness of the top plate 4 made of artificial marble, e.g. and thick in thickness by turning the plate A over to make the part 2 an upper face. On the other hand, the top plate 5 made of stainless, e.g. which is thin in thickness, is used by setting the part 2 to be a lower face to make the upper faces of the top plate 5 and the part 2 to be nearly one face.