To stably support a load on an auxiliary top plate unfolded, by connecting an auxiliary top plate at one side end of a main top plate through hinges and supporting these top plates by a link which is transferable from a position where only main top plate is supported on the support legs to another position where both main top plate and auxiliary top plate are supported by the support legs.

The top plate is constituted of a main top plate 3 and an auxiliary top plate 4 and two right and left connecting beam members 5a connecting a pair of front and rear legs 5 are connected by two beam members 7 to form the support legs 2. When extending the top plate 1, the auxiliary top plate 4 is set horizontally and pushed sideways. Then a link composed of a pair of crank rods 8, 9 is moved to push up the main top plate and the auxiliary top plate and separate them from the support legs 2 to transfer them to the right side. When further transferring them, both the main top plate 3 and the auxiliary top plate 4 are positioned on the support legs 2. In this way, only one side of the top plate 1 does not stick much from the support legs 2 even in the state the top plate is widened and hence, the table can avoid tumbling.