To automatically lock the standing state of a supporting leg by the standing operation of the supporting leg and to hold the folding state of the supporting leg in the case of folding the supporting leg in a table provided with foldable supporting legs at a lower surface of its top plate.

A guide hole 8 and an engaging hole 8a curved from the hole 8 are bored at a supporting leg holding member 5. An engaging pin 6 sliding in the guide hole 8 and the engaging hole 8a is formed at the supporting leg 4. A spring material 10 is provided at the supporting leg holding member 5. Then, when the supporting leg 4 is stood up from a state of being laid flatly, the engage pin 6 slides in the guide hole 8 and guided to the engaging hole 8a by the spring material 10. When the engage pin 6 is fitted in the engaging hole 8a, the fitting state is held elastically by the spring material 10 to be locked. When the supporting leg 4, is folded an engaging member 21 formed at the supporting leg 4 is fitted in an engaging hole 20 to hold the folding state of the supporting leg.